Indian Institute of Technology Palakkad&nbsp;(IIT Palakkad or IIT PKD) is a public autonomous&nbsp;engineering&nbsp;and&nbsp;research&nbsp;institute located in&nbsp;Palakkad,&nbsp;Kerala. It was&nbsp;one of the five new&nbsp;IITs&nbsp;proposed in the&nbsp;2014 Union budget of India. The campus was inaugurated on 3 August 2015. The institute has 94 faculty, 978 students, and 63 non-teaching staffs.

IT Palakkad currently offers four-year Bachelor of Technology (B.Tech) and two years MS programmes in 8 different engineering disciplines including&nbsp;Computer Science, Electrical, Mechanical, Civil among others.

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IIT Palakkad

Flame quenching by heat loss to a surface continues to be an active area of combustion research. Close wall temperature measurements in an isothermal wall-stabilized flame are reported in this work. Conventional N2-vibrational Coherent Anti-Stokes Raman Scattering (CARS) thermometry as close as 275 $\mu$m to a convex wall cooled with water has been carried out. The standard deviation of mean temperatures is observed to be $\sim$6.5% for high temperatures (>2000K) and $\sim$14% in the lower range (<500K). Methane/air and ethylene/air stoichiometric flames for various global strain rates based on exit bulk velocities are plotted and compared. CH* chemiluminescence is employed to determine the flame location relative to the wall. Flame locations are shown to move closer to the wall with increasing strain rates in addition to higher near-wall temperatures. Peak temperatures for ethylene are considerably higher ($\sim$250-300K) than peak temperatures for methane. Preheat zone profiles are similar for different strain rates across fuels. This work demonstrates close wall precise temperature measurments using CARS.

Department of Mechanical Engineering

World University root node

AIAA SciTech Forum - 55th AIAA Aerospace Sciences Meeting

Temperature measurements in a wall stabilized steady flame using CARS

This article reports on the quantification of the heating induced by nanosecond repetitively pulsed (NRP) glow discharges on a lean premixed methane-air flame. The flame, obtained at room temperature and atmospheric pressure, has an M-shape morphology. The equivalence ratio is 0.95 and the thermal power released by the flame is 113 W. The NRP glow discharges are produced by high voltage pulses of 10 ns duration, 7 kV amplitude, applied at a repetition frequency of 10 kHz. The average power of the plasma, determined from current and voltage measurements, is 1 W, i.e., about 0.9% of the thermal power of the flame. Broadband vibrational coherent anti-Stokes Raman spectroscopy of nitrogen is used to determine the temperature of the flame with and without plasma enhancement. The temperature evolution in the flame area shows that the thermal impact of NRP glow discharges is in the uncertainty range of the technique, i.e., ±40 K.

Fulltext

Combustion Science and Technology

Investigation of Gas Heating by Nanosecond Repetitively Pulsed Glow Discharges Used for Actuation of a Laminar Methane-Air Flame

We present Se77-NMR measurements on single-crystalline FeSe under pressures up to 2 GPa. Based on the observation of the splitting and broadening of the NMR spectrum due to structural twin domains, we discovered that static, local nematic ordering exists well above the bulk nematic ordering temperature, Ts. The static, local nematic order and the low-energy stripe-type antiferromagnetic spin fluctuations, as revealed by NMR spin-lattice relaxation rate measurements, are both insensitive to pressure application. These NMR results provide clear evidence for the microscopic cooperation between magnetism and local nematicity in FeSe. © 2017 American Physical Society.

Department of Physics

Physical Review B

NMR evidence for static local nematicity and its cooperative interplay with low-energy magnetic fluctuations in FeSe under pressure

A field evaluation of an underwater tunnel was conducted using a variety of nondestructive testing (NDT) methods, including visual inspection, air- and ground-coupled ground-penetrating radar (GPR), ultrasonic tomography (UST), and impact echo (IE). An air-coupled GPR antenna was used along with visual inspection to identify areas of interest in the Chesapeake Channel Tunnel near Norfolk, Virginia. After potential regions were identified, a robotic scanner with pneumatically driven suction feet was used to automatically scan the area using ground-coupled GPR, UST, and IE. Regions were also evaluated using manually applied UST. These methods combined with powerful software presented the element under inspection as a 3D volume for thorough inspection. This study shows that this particular combination of NDT techniques can efficiently and effectively identify and locate reinforcement, backwall depth, and potentially delaminated areas. By analyzing the phase shift of ultrasonic waves, it is also shown that UST techniques can be used to potentially determine the condition of the backwall and reinforcement bonding. © 2017 American Society of Civil Engineers.

Department of Civil Engineering

Journal of Infrastructure Systems

Nondestructive testing methods for underwater tunnel linings: Practical application at chesapeake channel tunnel

Recommending lifestyle articles is of immediate interest to theffecommerce industry and is beginning to attract research attention. Offen followed strategies, such as recommending popular items are inadequate for this vertical because of two reasons. Firstly, users have their own personal preference over items, referred to as personal styles, which lead to the long-tail phenomenon. Secondly, each user displays multiple personas, each persona has a preference over items which could be dictated by a particular occasion, e.g. dressing for a party would be different from dressing to go to o?ce. Recommendation in this vertical is crucially dependent on discovering styles for each of the multiple personas. There is no literature which addresses this problem. We posit a generative model which describes each user by a Simplex Over PERsona, SOPER, where a persona is described as the individuals preferences over prevailing styles modelled as topics over items. The choice of simplex and the long-tail nature necessitates the use of stick-breaking process. The main technical contribution is an efficient collapsed Gibbs sampling based algorithm for solving the attendant inference problem. Trained on large-scale interaction logs spanning more than halfa-million sessions collected from an e-commerce portal, SOPER outperforms previous baselines such as [9] by a large margin of 35% in identifying persona. Consequently it outperforms several competitive baselines comprehensively on the task of recommending from a catalogue of roughly 150 thousand lifestyle articles, by improving the recommendation quality as measured by AUC by a staggering 12:23%, in addition to aiding the interpretability of uncovered personal and fashionable styles thus advancing our precise understanding of the underlying phenomena. © 2017 ACM.

Department of Data Science

International Conference on Information and Knowledge Management, Proceedings

SOPER: Discovering the influence of fashion and the many faces of user from session logs using stick breaking process

International Conference on Advances in Construction Materials and Systems (2017)

Effect of Aggregate Gradation on Rutting Performance of Asphalt-Rubber Gap Graded Mixtures

The wild progenitors of major C4 crops grew as individuals subjected to little shading. Today they are grown in dense stands where most leaves are shaded. Do they maintain photosynthetic efficiency in these low light conditions produced by modern cultivation? The apparent maximum quantum yield of CO2 assimilation (φ CO2max, app ), a key determinant of light-limited photosynthesis, has not been systematically studied in field stands of C4 crops. φCO2max, app was derived from the initial slope of the response of leaf CO2 uptake (A) to photon flux (Q). Leaf fractional light absorptance (α) was measured to determine the absolute maximum quantum yield of CO2 assimilation on an absorbed light basis (φCO2max, abs ). Light response curves were determined on sun and shade leaves of 49 field plants of Miscanthus × giganteus and Zea mays following canopy closure. φCO2max, app and φCO2max, abs declined significantly by 15-27% (P&lt;0.05) with canopy depth. Experimentally, leaf age was shown unlikely to cause this loss. Modeling canopy CO2 assimilation over diurnal courses suggested that the observed decline in φCO2max, app with canopy depth costs 10% of potential carbon gain. Overcoming this limitation could substantially increase the productivity of major C4 crops. © The Author 2017. Published by Oxford University Press on behalf of the Society for Experimental Biology.

Environmental Sciences and Sustainable Engineering Centre (ESSENCE)

Journal of Experimental Botany

Loss of photosynthetic efficiency in the shade. An Achilles heel for the dense modern stands of our most productive C4 crops?

A generalised three-dimensional solver based on unstructured grid methodology has been developed for electrohydrodynamic flows. The Navier-Stokes equations with electrical field source term are solved in conjunction with the coupled electrical potential and ion charge density equations in a finite volume framework. An iterative boundary condition for updating the value of charge density on the discharge electrode is used while solving the electrical field equations. The solver is validated with available literature and the good agreement is found. © Springer India 2017.

Lecture Notes in Mechanical Engineering

Computation of flow coupled with the electric field on unstructured grid

In the present work for numerically investigating the interfacial flows, an algebraic Volume of Fluid technique has been implemented over hybrid unstructured meshes. Following the work of Dalal et al. (Numer Heat Transf Part B 54 (2):238–259, 2008 [2]), the governing equations are discretised by cell centered finite volume method wherein pressure-velocity coupling has been achieved by momentum interpolation due to Rhie and Chow (AIAA J 21:1525–1532, 1983 [12]). The binary fluid problem is represented by a single fluid formulation with a fluid property jump at the interface. Two schemes namely NVD based GAMMA scheme (Jasak, Int J Numer Meth Fluids 31:431–449, 1999 [7]) and Convergent and Universally Bounded Interpolation Scheme for the Treatment of Advection (CUBISTA) (Alves et al., Numer Heat Transf 49:19–42, 2006 [1]) has been incorporated into an in-house fully coupled Navier-Stokes solver. These schemes are validated with the published results of collapse of water column also known as dam break problem by Martin and Moyce (Math Phys Sci 244:312–324, 1952 [9]) and Rayleigh-Taylor instability (Tryggvason, J Comput Phys 75:253–282, 1988 [13]). The results are found to be in good agreement. © Springer India 2017.

A hybrid grid based algebraic volume of fluid method for interfacial flows

The influence of discrete and randomly distributed polyester (PET) fibers in improving the crack resistance and water-tightness of clay barriers was studied by conducting a series of centrifuge model tests at 40 gravities using a large beam centrifuge available at Indian Institute of Technology Bombay. Model clay barriers with and without fibers were subjected to flexural distress by inducing differential settlements using a settlement simulator. Two types of clay barriers were prepared by using two different types of soil, namely bentonite amended silty soil (Soil A) and kaolin clay-sand mixture (Soil B). Digital image cross-correlation (DIC) technique was used for analyzing the images captured by a digital photo camera and a charged couple device (CCD) camera, mounted along with the model. Unreinforced soil barriers (URSB) were found to lose their water-tightness and integrity at relatively lower distortion levels compared to identical fiber reinforced soil barriers (FRSB). Also, the performance of URSB and FRSB was found to be superior for Soil A compared to Soil B. The capability of PET fibers on preservation of existing unreinforced soil barriers was also demonstrated. The strain at crack initiation, εc, for FRSB is 2.90 and 2.36 times higher than identical URSB for Soil A and Soil B, respectively. Similarly, the strain at the onset of water breakthrough, εb, for FRSB is 2.14 and 2.79 times higher than identical URSB for Soil A and Soil B, respectively. There is a significant influence of fiber inclusion in retarding the crack initiation and water breakthrough at the onset of flexural distress for both the soil types. Thus, FRSB can withstand more distortion and strain while maintaining the integrity of the clay barrier. This observed behaviour of restraining cracks and improved performance of FRSB is primarily due to the reinforcement effect achieved due to soil-fiber interactions. © 2016 Elsevier B.V.