Showing papers by "Shiv Nadar University published in 2016"

Sustainable Sulfur-rich Copolymer/Graphene Composite as Lithium-Sulfur Battery Cathode with Excellent Electrochemical Performance.

Abstract: A sulfur-rich copolymer, poly(S-r-C-a) has been synthesized via a sustainable route, showing the utility of two major industrial wastes- elemental sulfur (petroleum waste) and cardanol (agro waste), to explore its potential as cathode material for Li-S batteries. The sulfur-rich copolymer exhibited a reduction in the active material dissolution into the electrolyte and a low self-discharge rate behavior during the rest time compared to an elemental sulfur cathode, indicating the chemical confinement of sulfur units. The presence of organosulfur moieties in copolymer suppress the irreversible deposition of end-discharge products on electrode surfaces and thus improve the electrochemical performances of Li-S batteries. This sulfur copolymer offered a reversible capacity of 892 mA h g−1 at 2nd cycle and maintained the capacity of 528 mA h g−1 after 50 cycles at 200 mA g−1. Reduced graphene oxide (rGO) prepared via a sustainable route was used as a conductive filler to extract the better electrochemical performances from this sulfur copolymer. Such sustainable origin batteries prepared via economically viable showed an improved specific capacity of ~975 mA h g−1 after 100 cycles at 200 mA g−1 current rate with capacity fading of 0.15% per cycle and maintained a stable performance over 500 cycles at 2000 mA g−1.

Spiro[pyrrolidine-3, 3´-oxindole] as potent anti-breast cancer compounds: Their design, synthesis, biological evaluation and cellular target identification

Abstract: The spiro[pyrrolidine-3, 3´-oxindole] moiety is present as a core in number of alkaloids with substantial biological activities. Here in we report design and synthesis of a library of compounds bearing spiro[pyrrolidine-3, 3´-oxindole] motifs that demonstrated exceptional inhibitory activity against the proliferation of MCF-7 breast cancer cells. The synthesis involved a one pot Pictet Spengler-Oxidative ring contraction of tryptamine to the desired scaffolds and occurred in 1:1 THF and water with catalytic trifluoroacetic acid and stoichiometric N-bromosuccinimide as an oxidant. Phenotypic profiling indicated that these molecules induce apoptotic cell death in MCF-7 cells. Target deconvolution with most potent compound 5l from the library, using chemical proteomics indicated histone deacetylase 2 (HDAC2) and prohibitin 2 as the potential cellular binding partners. Molecular docking of 5l with HDAC2 provided insights pertinent to putative binding interactions.

The Caspian Sea–Hindu Kush Index (CasHKI): A regulatory factor for dust activity over southwest Asia

Abstract: This work investigates the modulation in dust activity over southwest (SW) Asia attributed to changes in the mean sea level pressure (MSLP) between the Caspian Sea (CS) and Hindu Kush (HK) during the summer months (June–July–August–September, JJAS) of the period 2000–2014. The MSLP anomalies obtained via NCEP/NCAR re-analysis are evaluated via a new climatology index, the Caspian Sea–Hindu Kush Index (CasHKI), which is defined as CasHKI = MSLPanom.CS − MSLPanom.HK, over specific domains taken over the CS and HK. The changes in CasHKI intensity are examined against dust activity and rainfall distributions over south Asia. The satellite remote sensing (Meteosat, OMI, MODIS) analyses show that high CasHKI values corresponding to enhanced pressure gradient between the CS and the HK, are associated with intensification of northerly winds, increased dust emissions and transportation over SW Asia and north Arabian Sea. In contrast, variations in CasHKI intensity do not seem to have a significant effect on the Indian summer monsoon. Only a slight decrease of precipitation over the southern Indian peninsula and the neighboring oceanic areas and an increase of precipitation along the Ganges Basin and Himalayan range are found to be related to high CasHKI values. Model (MIROC-SPRINTARS) simulations of dust concentration and dust AOD (Aerosol Optical Depth) over SW Asia are consistent with the satellite observations, highlighting for the first time the modulation of the SW Asian dust activity by CasHKI.

A TISM modeling of critical success factors of smartphone manufacturing ecosystem in India

Abstract: Purpose – The purpose of this paper is to identify and analyze various critical success factors (CSFs) that can facilitate smartphone manufacturing in India. This paper further aims to understand the mutual interactions among these CSFs through identification of the hierarchical relationships among them. Design/methodology/approach – A framework for a smartphone manufacturing system has been developed, wherein the hierarchical inter-relationships between identified CSFs have been presented and interpreted using total interpretive structural modeling (TISM). Cross-impact matrix multiplication applied to classification analysis has been further employed to identify the driving power as well as dependence power of these CSFs. Findings – In the present research, 15 CSFs have been identified through literature review and expert opinions. The hierarchical framework developed using TISM has revealed the inter-dependencies among these CSFs. This research further categorizes CSFs into three clusters. The first clu...

Tool condition monitoring by SVM classification of machined surface images in turning

Abstract: Tool condition monitoring has found its importance to meet the requirement of quality production in industries. Machined surface is directly affected by the extent of tool wear. Hence, by analyzing the machined surface, the information about the cutting tool condition can be obtained. This paper presents a novel technique for multi-classification of tool wear states using a kernel-based support vector machine (SVM) technique applied on the features extracted from the gray-level co-occurrence matrix (GLCM) of machined surface images. The tool conditions are classified into sharp, semi-dull, and dull tool states by using Gaussian and polynomial kernels. The proposed method is found to be cost-effective and reliable for online tool wear classification.

SmartVent: A Context Aware IoT System to Measure Indoor Air Quality and Ventilation Rate

Abstract: As humans generally spend most of their time indoors, having good indoor air quality and its real time information is critical for maintaining human health and productivity. According to EPA, indoor air even in centrally air-conditioned buildings is several times more polluted than outdoor air, primarily due to change in occupancy pattern, poor, old or ill maintained ventilation systems, dust, and presence of volatile organic compounds. Hence, it is necessary for humans to pervasively and ubiquitously measure air quality information in real time, specially whose health is sensitive to poor indoor air. In this work, we propose a novel context aware Android smart phone based mobile adhoc sensing system that senses various data from indoor environment around the user and analyses it in real time, thereby helping to maintain good health and better work productivity.

Cardanol benzoxazine‐Sulfur Copolymers for Li‐S batteries: Symbiosis of Sustainability and Performance

Abstract: A sulfur-rich copolymer is synthesized via a sustainable, eco-friendly approach using two major wastes namely, elemental sulfur (industrial waste) and cardanol (agro waste) and its application as cathode active material in Li−S battery. The presence of chemically bound sulfur (90 wt%) utilising cardanol (10 wt%) derivative in the copolymer (S90) showed a reduction in the active material dissolution into the electrolyte. In addition, the organic sulfur units get dispersed into the insoluble/insulating Li2S2/Li2S phase and thus found to suppress their irreversible deposition. Li−S battery based on S90/multi-walled carbon nanotubes (MWCNT) (10 wt%) exhibited a reversible capacity of 1302 mAh g−1 at 2nd cycle, maintaining a high reversible capacity of 928 mAh g−1 after 70 cycles at a relatively constant coulombic efficiency over 99 % at current rate of 200 mA g−1. At 1000 mA g−1 current rate, the composite cathode delivered a reversible capacity of 697 mAh g−1 at 2nd cycle and retained 75 % of its initial capacity even after 180 cycles.

Monitoring conformational heterogeneity of the lid of DnaK substrate-binding domain during its chaperone cycle.

Abstract: DnaK or Hsp70 of Escherichia coli is a master regulator of the bacterial proteostasis network. Allosteric communication between the two functional domains of DnaK, the N-terminal nucleotide-binding domain (NBD) and the C-terminal substrate- or peptide-binding domain (SBD) regulate its activity. X-ray crystallography and NMR studies have provided snapshots of distinct conformations of Hsp70 proteins in various physiological states; however, the conformational heterogeneity and dynamics of allostery-driven Hsp70 activity remains underexplored. In this work, we employed single-molecule Forster resonance energy transfer (sm-FRET) measurements to capture distinct intradomain conformational states of a region within the DnaK-SBD known as the lid. Our data conclusively demonstrate prominent conformational heterogeneity of the DnaK lid in ADP-bound states; in contrast, the ATP-bound open conformations are homogeneous. Interestingly, a nonhydrolysable ATP analogue, AMP-PNP, imparts heterogeneity to the lid conformations mimicking the ADP-bound state. The cochaperone DnaJ confers ADP-like heterogeneous lid conformations to DnaK, although the presence of the cochaperone accelerates the substrate-binding rate by a hitherto unknown mechanism. Irrespective of the presence of DnaJ, binding of a peptide substrate to the DnaK-SBD leads to prominent lid closure. Lid closure is only partial upon binding to molten globule-like authentic cellular substrates, probably to accommodate non-native substrate proteins of varied structures.

Multilevel programming in Cu/NiO y /NiO x /Pt unipolar resistive switching devices.

Abstract: The application of a NiO y /NiO x bilayer in resistive switching (RS) devices with x > y was studied for its ability to achieve reliable multilevel cell (MLC) characteristics. A sharp change in resistance brought about by sweeping the voltage, along with an improved on/off ratio (>103) and endurance (104) were achieved in the bilayer structure as compared to the single NiO x layer devices. Moreover, it was found that nonvolatile and stable resistance levels, especially the multiple low-resistance states of Cu/NiO y /NiO x /Pt memory devices, could be controlled by varying the compliance current. All the multilevel resistance states of the Cu/NiO y /NiO x /Pt bilayer devices were stable for up to 500 consecutive dc switching cycles, as compared to the Cu/NiO x /Pt single layer devices. The temperature-dependent variation of the high and low resistance states of both the bilayer and single layer devices was further investigated to elucidate the charge conduction mechanism. Finally, based on a detailed analysis of the experimental results, comparisons of the possible models for RS in bilayer and single layer memory devices have also been discussed.

Prediction of polymer properties using infinite chain descriptors (ICD) and machine learning: Toward optimized dielectric polymeric materials

Abstract: To facilitate the development of new polymeric materials, we report the development of new heuristic models to predict the dielectric constant, band gap, dielectric loss tangent, and glass transition temperatures for organic polymers. A new set of features called infinite chain descriptors (ICDs) was designed and developed especially to characterize organic polymers, utilizing methods with minimal dependence on predefined fragment libraries. Machine learning models were built for the aforementioned properties incorporating best practices in the field such as objective feature selection, cross-validation and external test sets. All models produced in this study showed good performance in prediction. A web tool has been developed and has been made available that supports the input of novel structures. VC 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2016, 54, 2082–2091

Isostructural polymorphs: qualitative insights from energy frameworks

Abstract: Three isostructural polymorphs with two-dimensional and three-dimensional similarities are demonstrated quantitatively from similarity relationship analysis. The similarity dimensions are then visualized and correlated in a novel way via qualitative analysis using ‘energy frameworks’. Two of the three polymorphs with three-dimensional similarities exhibiting identical physical properties have almost equi-energetic crystal structures while the most stable third polymorph exhibits distinct properties. Thereby, structure–property correlations are derived, both quantitatively and qualitatively.

Multilevel resistance state of Cu/La2O3/Pt forming-free switching devices

Abstract: An improved temperature dependent uniformity and reliability is investigated in La2O3/Pt-based memory devices with Cu top electrode. The microstructural investigation suggested the formation of polycrystalline La2O3 layer with stoichiometric chemical composition confirmed by X-ray photoelectron spectroscopy. Besides showing a forming-free resistive switching (RS) behaviour, the device also exhibited excellent multilevel capability with low switching voltage. A uniformity in the SET/RESET process was observed indicating enhanced switching stability. In addition, endurance with a high ON/OFF ratio of the order 103 and satisfactory data retention time over 104 s at 85 °C temperature confirmed the reliability of memory cells. Intrinsic tailoring of switching mechanism has been discussed in the framework of electric field-induced creation and annihilation of the reproducible Cu filaments in switching layer. The metallic nature of conducting filament has further been confirmed by temperature-dependent RS characterization.

Synthesis of Quinazolines and Dihydroquinazolines: o-Iodoxybenzoic Acid Mediated Tandem Reaction of o-Aminobenzylamine with Aldehydes

Abstract: We have demonstrated a facile synthesis of diversely substituted quinazolines and 3,4-dihydroquinazolines through the o-iodoxybenzoic acid (IBX) mediated tandem reaction of readily available o-aminobenzylamine and aldehydes. The yield of the reactions generally ranged from 70% to 95%. This mild protocol provides an efficient strategy toward the synthesis of these classes of heterocycles.

A paraphrase and semantic similarity detection system for user generated short-text content on microblogs

Abstract: Existing systems deliver high accuracy and F1-scores for detecting paraphrase and semantic similarity on traditional clean-text corpus. For instance, on the clean-text Microsoft Paraphrase benchmark database, the existing systems attain an accuracy as high as 0:8596. However, existing systems for detecting paraphrases and semantic similarity on user-generated short-text content on microblogs such as Twitter, comprising of noisy and ad hoc short-text, needs significant research attention. In this paper, we propose a machine learning based approach towards this. We propose a set of features that, although well-known in the NLP literature for solving other problems, have not been explored for detecting paraphrase or semantic similarity, on noisy user-generated short-text data such as Twitter. We apply support vector machine (SVM) based learning. We use the benchmark Twitter paraphrase data, released as a part of SemEval 2015, for experiments. Our system delivers a paraphrase detection F1-score of 0.717 and semantic similarity detection F1-score of 0.741, thereby significantly outperforming the existing systems, that deliver F1-scores of 0.696 and 0.724 for the two problems respectively. Our features also allow us to obtain a rank among the top-10, when trained on the Microsoft Paraphrase corpus and tested on the corresponding test data, thereby empirically establishing our approach as ubiquitous across the different paraphrase detection databases.

Extended mhd turbulence and its applications to the solar wind

Abstract: Extended MHD is a one-fluid model that incorporates two-fluid effects such as electron inertia and the Hall drift. This model is used to construct fully nonlinear Alfvenic wave solutions, and thereby derive the kinetic and magnetic spectra by resorting to a Kolmogorov-like hypothesis based on the constant cascading rates of the energy and generalized helicities of this model. The magnetic and kinetic spectra are derived in the ideal $\left(k 1/\lambda_e\right)$ regimes; $k$ is the wavenumber and $\lambda_s = c/\omega_{p s}$ is the skin depth of species `$s$'. In the Hall regime, it is shown that the emergent results are fully consistent with previous numerical and analytical studies, especially in the context of the solar wind. The focus is primarily on the electron inertia regime, where magnetic energy spectra with power-law indexes of $-11/3$ and $-13/3$ are always recovered. The latter, in particular, is quite close to recent observational evidence from the solar wind with a potential slope of approximately $-4$ in this regime. It is thus plausible that these spectra may constitute a part of the (extended) inertial range, as opposed to the standard `dissipation' range paradigm.

The child brain computes and utilizes internalized maternal choices

Abstract: As children grow, they gradually learn how to make decisions independently. However, decisions like choosing healthy but less-tasty foods can be challenging for children whose self-regulation and executive cognitive functions are still maturing. We propose a computational decision-making process in which children estimate their mother’s choices for them as well as their individual food preferences. By employing functional magnetic resonance imaging during real food choices, we find that the ventromedial prefrontal cortex (vmPFC) encodes children’s own preferences and the left dorsolateral prefrontal cortex (dlPFC) encodes the projected mom’s choices for them at the time of children’s choice. Also, the left dlPFC region shows an inhibitory functional connectivity with the vmPFC at the time of children’s own choice. Our study suggests that in part, children utilize their perceived caregiver’s choices when making choices for themselves, which may serve as an external regulator of decision-making, leading to optimal healthy decisions. Mothers advocate eating healthy foods while children like to eat tasty foods. Lim and colleagues demonstrate that children incorporate their mothers' food choices while deciding what to eat as well as provide the neural correlates of this decision making process.

Integrated design of preventive maintenance and quality control policy parameters with CUSUM chart

Abstract: Performance of a production system depends on breakdown-free operation of equipment and processes. Maintenance and quality control play an important role in achieving this goal. This paper presents an integrated model for joint optimization of preventive maintenance and quality control policy with cumulative sum (CUSUM) control chart parameters. Two types of maintenance policies are considered, namely minimal corrective maintenance and imperfect preventive maintenance. The proposed model enables the determination of the optimal value of each of the five decision variables, i.e. sample size (n), sample interval (h), the reference value (K), the decision interval (h 1) and preventive maintenance interval (t PM), that minimize the expected total system cost per unit time. A numerical example is presented to demonstrate the effect of the cost parameters on the integrated design of preventive maintenance and quality control policy. It also compares the system performance employing the proposed integrated approach with that obtained by considering maintenance and CUSUM chart independently. Substantial economic benefit of 19 % is seen in the joint optimization.

Multifunctional reduced graphene oxide coated cloths for oil/water separation and antibacterial application

Abstract: Multifunctional reduced graphene oxide (RGO) coated cloths were prepared through the thermal treatment of GO coated cloths without using any harmful reducing agent. The effect of heating temperature on the wetting properties of the cloths was also monitored through contact angle measurement. The highest contact angle 141° was observed for the RGO coated dense cloth while the highest contact angle exhibited by the RGO coated sparse cloth was 130°. The as prepared RGO coated cloths were utilized as a filter and an absorbent for oil/water separation. The RGO coated sparse cloth was utilized as a filter for the separation of an oil/water mixture while the dense cloth was utilized as an absorbent for the selective absorption of oil from water. RGO coated cloths were also explored as an antibacterial agent and the effect of the microstructure of coated cloths on their antibacterial properties was also investigated. The cloth with the dense structure exhibited higher antibacterial activity compared to the sparse cloth. A significant loss of percentage viability up to 98% was achieved using the RGO coated cloth, proving it highly efficient as an antibacterial agent, which makes it a suitable bandage material for the dressing of open wounds. Apart from being antibacterial, the RGO coated cloths are also hydrophobic in nature so they can protect wound from water and atmospheric moisture which is not possible with ordinary bandages.