Environmental Sciences and Sustainable Engineering Centre (ESSENCE)

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.

&nbsp;

IIT Palakkad

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.

World University root node

Fulltext

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?

In order to enable the adoption of fibre reinforced concrete (FRC) in applications such as slabs-on-grade, it is imperative to develop comprehensive guidelines that address different facets of the slab behavior. The current study aims at providing a design methodology for FRC slabs-on-grade and pavements, which incorporates suitable material parameters and considers various failure conditions. The approach is based on inelastic analysis since the presence of fibres imparts sufficient rotation capacity to the slabs. The equivalent flexural strength, fiflα150fifl is used to incorporate the crack resisting potential in the design. The required expressions are developed based on yield line analysis for different types of loads and lead to performance requirements in terms of the equivalent flexural strength, for a minimum thickness and chosen grade of concrete, by using appropriate limiting moment equations. The methodology also accounts for stresses due to temperature variations and restraint to shrinkage. A detailed calculation is also given to illustrate the use of the design procedure.

Indian Concrete Journal

Design methodology for fibre reinforced concrete slabs-on-grade based on inelastic analysis

The effective utilization of pseudo‐ductile materials like Fibre Reinforced Concrete (FRC) depends on the incorporation of suitable material parameters in appropriate design approaches. A design methodology has been developed for slabs‐on‐grade addressing various failure patterns and giving a performance requirement as the design output. This opens up the choice of fibres, allowing the use of combinations of fibres to suit the service requirements. In this context, the current study explores the use of hybrid combinations of conventional steel fibres (SF) and a genre of corrosionresistant amorphous metallic fibres (AMF) that have the ability to significantly enhance the flexural strength of concrete, even at relatively low dosages. It is shown that AMF, when used in combination with SF, results in a synergistic response with respect to toughness; mixes with 15 kg/m3 of SF and 20 kg/m3 of AMF exhibit about 50% higher characteristic flexural strength and more than double the characteristic equivalent flexural strength than the mix with 15 kg/m3 of SF alone, in the concrete considered here. Consequently, when FRC with a hybrid combination of fibres (AMF+SF) was considered in design, a significant reduction in thickness of slab was possible, in comparison to FRC with only SF.

RILEM Technical Letters

Benefits of using amorphous metallic fibres in concrete slabs‐on‐grade

To achieve the goals of energy security and climate change mitigation in Denmark and the EU, an expansion of national production of bioenergy crops is needed. Temporal and spatial variation of yields of willow and Miscanthus is not known for Denmark because of a limited number of field trial data. The semi-mechanistic crop model BioCro was used to simulate the production of both short-rotation coppice (SRC) willow and Miscanthus across Denmark. Predictions were made from high spatial resolution soil data and weather records across this area for 1990–2010. The potential average, rain-fed mean yield was 12.1 Mg DM ha−1 yr−1 for willow and 10.2 Mg DM ha−1 yr−1 for Miscanthus. Coefficient of variation as a measure for yield stability was poorest on the sandy soils of northern and western Jutland, and the year-to-year variation in yield was greatest on these soils. Willow was predicted to outyield Miscanthus on poor, sandy soils, whereas Miscanthus was higher yielding on clay-rich soils. The major driver of yield in both crops was variation in soil moisture, with radiation and precipitation exerting less influence. This is the first time these two major feedstocks for northern Europe have been compared within a single modeling framework and providing an important new tool for decision-making in selection of feedstocks for emerging bioenergy systems. © 2015 The Authors. Global Change Biology Bioenergy Published by John Wiley & Sons Ltd.

GCB Bioenergy

Comparing predicted yield and yield stability of willow and Miscanthus across Denmark

Doctoral Thesis, Department of Civil Engineering, Indian Institute of {\ldots}

Design of Fibre Reinforced Concrete Slabs-ongrade and Pavements

High-performance computing has facilitated development of biomass production models that capture the key mechanisms underlying production at high spatial and temporal resolution. Direct responses to increasing [CO2] and temperature are important to long-lived emerging woody bioenergy crops. Fast-growing willow (Salix spp.) within short rotation coppice (SRC) has considerable potential as a renewable biomass source, but performance over wider environmental conditions and under climate change is uncertain. We extended the bioenergy crop modeling platform, BioCro, to SRC willow by adding coppicing and C3 photosynthesis subroutines, and modifying subroutines for perennation, allocation, morphology, phenology and development. Parameterization with measurements of leaf photosynthesis, allocation and phenology gave agreement of modeled with measured yield across 23 sites in Europe and North America. Predictions for the continental USA suggest yields of ≥17Mgha-1year-1 in a 4 year rotation. Rising temperature decreased predicted yields, an effect partially ameliorated by rising [CO2]. This model, based on over 100 equations describing the physiological and biophysical mechanisms underlying production, provides a new framework for utilizing mechanism of plant responses to the environment, including future climates. As an open-source tool, it is made available here as a community resource for further application, improvement and adaptation. Willows in short rotation coppicing are emerging as major sustainable feedstocks for bioenergy. As long-lived C3 crops, they will experience significant global change. Within the BioCro framework we have developed a new model for this crop that captures the key mechanisms of response to rising atmospheric CO2, temperature and precipitation to predict yield and yield stability across the USA. The model, is mechanistically rich and based on over 100 equations describing the physiological and biophysical mechanisms underlying production. It showed a good ability to predict recorded yields at a range of sites in Europe and N. America given soil and climate data. High yields, exceeding those of the perennial C4 grass feedstocks Miscanthus and switchgrass were predicted across much of the north-east USA, reaching &gt;17 Mt ha-1 yr-1 at the best locations. Rising temperatures over this century decreased yields, an effect partially ameliorated by rising [CO2]. Using the BioCro framework, common to other perennial feedstocks, avoids confounding biological differences in species comparisons with differences in model structure and model assumptions. As an open-source tool, it is made available here as a community resource for further application, improvement, and adaptation. © 2015 The Authors. Plant, Cell & Environment published by John Wiley & Sons Ltd.

Plant Cell and Environment

A physiological and biophysical model of coppice willow (Salix spp.) production yields for the contiguous USA in current and future climate scenarios

A study on the use of amorphous metallic fibers (AMFs) in concrete was undertaken to combine its action with that of hooked-ended steel fibers for improving flexural strength and toughness. Tests on mixtures with various dosages of AMF (10, 20 and 30 kg/m3 [16.9, 33.7 and 50.6 lb/yd3]) and 15 kg/m3 (25.3 lb/yd3) of steel fibers were carried out, along with hybrid mixtures with two dosages of AMF. The results showed a significant increase in the flexural strength of concrete with the addition of AMF, even at low dosages. The performance of concretes with the hybrid combinations is significantly enhanced. For example, the equivalent flexural strength for the concretes with just 10 kg/m3 (16.9 lb/yd3) of AMF and 15 kg/m3 (25.3 lb/yd3) of steel fibers is 35% higher than with only steel fibers and is approximately 3.5 times that obtained with only 10 kg/m3 (16.9 lb/yd3) of AMF. The load-deflection behavior and the toughness parameters clearly indicate a significant synergy in the hybrid combination.

ACI Materials Journal

Synergy in toughness by incorporating amorphous metal and steel fibers

We develop an integrated framework to determine and compare greenhouse gas (GHG) intensities and production costs of cellulosic ethanol derived from corn stover, switchgrass, and miscanthus grown on high and low quality soils for three representative counties in the Eastern United States. This information is critical for assessing the cost-effectiveness of utilizing cellulosic ethanol for mitigating GHG emissions and designing appropriate policy incentives to support cellulosic ethanol production nationwide. We find considerable variations in the GHG intensities and production costs of ethanol across feedstocks and locations mostly due to differences in yields and soil characteristics. As compared to gasoline, the GHG savings from miscanthus-based ethanol ranged between 130% and 156% whereas that from switchgrass ranged between 97% and 135%. The corresponding range for GHG savings with corn stover was 57% to 95% and marginally below the threshold of at least 60% for biofuels classified as cellulosic biofuels under the Renewable Fuels Standard. Estimates of the costs of producing ethanol relative to gasoline imply an abatement cost of at least $48 Mg-1 of GHG emissions (carbon dioxide equivalent) abated and can be used to infer the minimum carbon tax rate needed to induce consumption of cellulosic ethanol. © 2015 American Chemical Society.