IIT Madras is a public technical and research university located in Chennai, Tamil Nadu. Founded in 1959, it is recognised as an Institute of National Importance.

IIT Madras has been ranked as the top engineering institute in India for four years in a row by the National Institutional Ranking Framework of the MHRD

It currently offers undergraduate, postgraduate and research degrees across 16 disciplines in Engineering, Sciences, Humanities and Management. About 596 faculty belonging to science and engineering departments and centres of the Institute are engaged in teaching, research and industrial consultancy.

IIT Madras

This study examines the extent to which financing constraints affect the research and development (R&D) expenditure of Indian manufacturing firms during the period 1991-2011. Using dynamic R&D investment model, we find significant positive relationship between a firm's R&D expenditure and internal cash flow. We lend support to the financing constraint hypothesis by showing higher cash flow sensitivity for small and young firms. Further, we explore the effect of business group affiliation and financial market liquidity on the relationship between financial factors and investments in R&D. We fail to find any significant advantage for group-affiliated firms, indicating ineffectiveness of business groups in alleviating financial constraints. Further, we observe that sample firms do not use external equity to finance their R&D even during periods of hot-equity market and are not engaging in R&D smoothing using cash reserves. © 2014 The Board of Trustees of the University of Illinois.

Department of Humanities and Social Sciences

Quarterly Review of Economics and Finance

Financing constraints and investments in R and D: Evidence from Indian manufacturing firms

This article is an attempt to empirically analyze the technology behaviour (R&D) of the Indian Pharmaceutical Industry (IPI) during the post Trade Related Aspects of Intellectual Property Rights (TRIPS) regime. This study is based on firm level data of 424 firms belonging to the IPI for the period 1994–2010. The empirical analysis is based on pooled cross sectional and random effects panel tobit models. The results of the study indicate that the TRIPS regime had a significant positive impact on R&D in the IPI. Firms owned by Indian groups are found to be more R&D intensive compared to stand-alone private and foreign firms. Further, export intensity and size are found to have significant impact on R&D intensity. © 2014 IMI SAGE Publications.

Fulltext

Global Business Review

Do Stronger IPR Regimes Influence R&D Efforts? Evidence from the Indian Pharmaceutical Industry

The present study investigates the growth barriers of informal sector enterprises in India. The empirical analysis is based on the National Sample Survey Organization's unit-level data for three years, 2000-2001, 2005-6, and 2010-11. The results of the study reveal: proprietary and large firms survive and grow; enterprises managed by women are less likely to decline; inadequate power supply poses a severe growth obstacle to all categories of firms; and proprietary firms encounter capital shortage while large firms are constrained by the non-availability of raw materials. We do not find evidence of sub-contracting acting as an enabling factor in firm growth. © 2014 Institute of Developing Economies.

Developing Economies

The Growth Barriers of Informal Sector Enterprises: Evidence from India

The entry of foreign firms in India since the reforms forces domestic firms to undertake R&amp;D activities or import technology so as to compete with them. This study examines the relationship between FDI and R&amp;D of the domestic firms in the post-liberalization regime. The study uses unbalanced panel data for 1,843 Indian manufacturing firms operating during the period 1994–2005 and corrects for the self-selection problem by using a Heckman-two step procedure. The analysis involving full sample does not give a clear picture of the impact of FDI on the innovation strategies of domestic firms. Interesting results emerge, when analysis is carried out according to different sub-samples—based on foreign-ownership and technology intensity of the industry. FDI and R&amp;D are found to be complements when sample is divided on the bases of equity ownership. FDI inflow induces foreign-owned firms in high tech industries and firms in minority ownership to invest in R&amp;D.

World University root node

World Development

Foreign Direct Investment and R&amp;D: Substitutes or Complements—A Case of Indian Manufacturing after 1991 Reforms

One of the most intriguing aspects of the recent empirical literature on FDI-related spillover effects is the increasing identification of mixed results. A few studies, particularly in advanced countries have found positive effects; however, a more common scenario in recent studies is the prevalence of insignificant or even negative effects. This is despite the fact that theory predicts substantial positive effects in association with a supposed technological superiority of MNCs relative to domestic firms, particularly in the context of less advanced countries. In this paper, by distinguishing subsidiaries according to their orientation to carry out creative vs. exploitation activities in the host economy, we are able to distinguish situations with positive and negative spillover effects, and we explain why they may be emerging. More specifically, we find that only subsidiaries that are oriented to technologically creative activities have a significantly positive effect in India. In contrast, subsidiaries oriented mostly to technologically exploitative activities generate negative effects in some circumstances. The implications for theory and policy are discussed. © 2010 Elsevier B.V. All rights reserved.

Research Policy

Heterogeneous MNC subsidiaries and technological spillovers: Explaining positive and negative effects in India

The present study provides some empirical evidence for the export spillover effect examining the case of an emerging market economy, namely India, using firm level data for the period 1994-2006. We disentangle different spillover channels, namely the demonstration effect, the imitation effect (R&D spillover) and a proxy to measure spillover effects coming from higher MNEs' skills. We also account for the heterogeneous technological behaviour of local firms considering how in-house R&D efforts and disembodied technological imports may affect the exporting performance. Our findings show how export spillover effects are mainly mediated by an imitation effect, contrary to the case of other emerging market economies like China, where a demonstration effect is evident. We also recognise that both the decision to export and export intensity are influenced most of all by the technological activities of local firms. Moreover, the findings of the analysis suggest that in-house R&D is more relevant than other external sources of technological knowledge such as disembodied technology imports to internalise the positive spillover effect emanating from MNEs. © 2010 Elsevier B.V.

Economic Systems

MNEs, technological efforts and channels of export spillover: An analysis of Indian manufacturing industries

This paper presents a general concept and mathematical framework of particle hygroscopicity distribution for the analysis and modeling of aerosol hygroscopic growth and cloud condensation nucleus (CCN) activity. The cumulative distribution function of particle hygroscopicity, H(k,Dd) is defined as the number fraction of particles with a given dry diameter, (Hk,D d,) and with an effective hygroscopicity parameter smaller than the parameter.K From hygroscopicity tandem differential mobility analyzer (HTDMA) and size-resolved CCN measurement data, (Hk,Dd) can be derived by solving the k-Köhler model equation. Alternatively, H(k,d) can be predicted from measurement or model data resolving the chemical composition of single particles. A range of model scenarios are used to explain and illustrate the concept, and exemplary practical applications are shown with HTDMA and CCN measurement data from polluted megacity and pristine rainforest air. Lognormal distribution functions are found to be suitable for approximately describing the hygroscopicity distributions of the investigated atmospheric aerosol samples. For detailed characterization of aerosol hygroscopicity distributions, including externally mixed particles of low hygroscopicity such as freshly emitted soot, we suggest that size-resolved CCN measurements with a wide range and high resolution of water vapor supersaturation and dry particle diameter should be combined with comprehensive HTDMA measurements and size-resolved or single-particle measurements of aerosol chemical composition, including refractory components. In field and laboratory experiments, hygroscopicity distribution data from HTDMA and CCN measurements can complement mixing state information from optical, chemical and volatility-based techniques. Moreover, we propose and intend to use hygroscopicity distribution functions in model studies investigating the influence of aerosol mixing state on the formation of cloud droplets. © Author(s) 2010.

Department Of Civil Engineering

Department Of Biotechnology

Atmospheric Chemistry and Physics

Hygroscopicity distribution concept for measurement data analysis and modeling of aerosol particle mixing state with regard to hygroscopic growth and CCN activation

The Amazon is one of the few continental regions where atmospheric aerosol particles and their effects on climate are not dominated by anthropogenic sources. During the wet season, the ambient conditions approach those of the pristine pre-industrial era. We show that the fine submicrometer particles accounting for most cloud condensation nuclei are predominantly composed of secondary organic material formed by oxidation of gaseous biogenic precursors. Supermicrometer particles, which are relevant as ice nuclei, consist mostly of primary biological material directly released from rainforest biota. The Amazon Basin appears to be a biogeochemical reactor, in which the biosphere and atmospheric photochemistry produce nuclei for clouds and precipitation sustaining the hydrological cycle. The prevailing regime of aerosol-cloud interactions in this natural environment is distinctly different from polluted regions.

Department of Mechanical Engineering

Science

Rainforest aerosols as biogenic nuclei of clouds and precipitation in the Amazon

We have investigated the formation of cloud droplets under pyro-convective conditions using a cloud parcel model with detailed spectral microphysics and with the κ-Köhler model approach for efficient and realistic description of the cloud condensation nucleus (CCN) activity of aerosol particles. Assuming a typical biomass burning aerosol size distribution (accumulation mode centred at 120 nm), we have calculated initial cloud droplet number concentrations (NCD) for a wide range of updraft velocities (w=0.25-20ms-1) and aerosol particle number concentrations (N CAT=200-105cm-3) at the cloud base. Depending on the ratio between updraft velocity and particle number concentration (w/NCN), we found three distinctly different regimes of CCN activation and cloud droplet formation: (1) An aerosol-limited regime that is characterized by high w/NCN ratios (&gt;≈10-3ms -1 cm3), high maximum values of water vapour supersaturation (Smax≈ 0.5%), and high activated fractions of aerosol particles (NCD/NCN≈90%). In this regime N CD D is directly proportional to NcN and practically independent of w. (2) An updraft-limited regime that is characterized by low w/NCN ratios ( &lt; ≈10-4 ms-1 cm3), low maximum values of water vapour supersaturation (Smax&lt;≈0.2%), and low activated fractions of aerosol particles (NCD/NCN &lt;≈20%). In this regime NCD is directly proportional to w and practically independent of NCN-(3) An aerosol- and updraft-sensitive regime (transitional regime), which is characterized by parameter values in between the two other regimes and covers most of the conditions relevant for pyro-convection. In this regime NCD depends non-linearly on both NCN and w. In sensitivity studies we have tested the influence of aerosol particle size distribution and hygroscopicity on NCD Within the range of effective hygroscopicity parameters that is characteristic for continental atmospheric aerosols (κ≈0.05-0.6), we found that N CD depends rather weakly on the actual value of κ. A compensation of changes in κ and Smax leads to an effective buffering of NCD. Only for aerosols with very low hygroscopicity (κ &lt;0.05) and also in the updraft-limited regime for aerosols with higher than average hygroscopicity (κ&gt;0.3) did the relative sensitivities ∂lnNCD/∂lnκ/≈(△N CD/△NCD)/(△κ/κ) exceed values of ∼0.2, indicating that a 50% difference in κ would change N CD by more than 10%. The influence of changing size distribution parameters was stronger than that of particle hygroscopicity. Nevertheless, similar regimes of CCN activation were observed in simulations with varying types of size distributions (polluted and pristine continental and marine aerosols with different proportions of nucleation, Aitken, accumulation, and coarse mode particles). In general, the different regimes can be discriminated with regard to the relative sensitivities of NCD against w and N CN (∂lnNCD/∂lw and ∂lnNCD/ ∂lnNCN)We propose to separate the different regimes by relative sensitivity ratios, (∂nNCD/∂lnw)/(∂lnN CD/∂lnNCN) of 4:1 and 1:4, respectively. The results of this and related studies suggest that the variability of initial cloud droplet number concentration in convective clouds is mostly dominated by the variability of updraft velocity and aerosol particle number concentration in the accumulation and Aitken mode. Coarse mode particles and the variability of particle composition and hygroscopicity appear to play major roles only at low supersaturation in the updraft-limited regime of CCN activation (5max0.2%).

Aerosol- and updraft-limited regimes of cloud droplet formation: Influence of particle number, size and hygroscopicity on the activation of cloud condensation nuclei (CCN)

This study was part of the international field measurement Campaigns of Air Quality Research in Beijing and Surrounding Region 2006 (CAREBeijing-2006). We investigated a new particle formation event in a highly polluted air mass at a regional site south of the megacity Beijing and its impact on the abundance and properties of cloud condensation nuclei (CCN). During the 1-month observation, particle nucleation followed by significant particle growth on a regional scale was observed frequently (∼30%), and we chose 23 August 2006 as a representative case study. Secondary aerosol mass was produced continuously, with sulfate, ammonium, and organics as major components. The aerosol mass growth rate was on average 19 μg m-3 h-1 during the late hours of the day. This growth rate was observed several times during the 1-month intensive measurements. The nucleation mode grew very quickly into the size range of CCN, and the CCN size distribution was dominated by the growing nucleation mode (up to 80% of the total CCN number concentration) and not as usual by the accumulation mode. At water vapor supersaturations of 0.07-0.86%, the CCN number concentrations reached maximum values of 4000-19,000 cm -3 only 6-14 h after the nucleation event. During particle formation and growth, the effective hygroscopicity parameter κ increased from about 0.1-0.3 to 0.35-0.5 for particles with diameters of 40-90 nm, but it remained nearly constant at ∼ 0.45 for particles with diameters of ∼ 190 nm. This result is consistent with aerosol chemical composition data, showing a pronounced increase of sulfate. Copyright 2009 by the American Geophysical Union.

Journal of Geophysical Research Atmospheres

Rapid aerosol particle growth and increase of cloud condensation nucleus activity by secondary aerosol formation and condensation: A case study for regional air pollution in northeastern China

Size-resolved chemical composition, mixing state, and cloud condensation nucleus (CCN) activity of aerosol particles in polluted mega-city air and biomass burning smoke were measured during the PRIDE-PRD2006 campaign near Guangzhou, China, using an aerosol mass spectrometer (AMS), a volatility tandem differential mobility analyzer (VTDMA), and a continuous-flow CCN counter (DMT-CCNC). The size-dependence and temporal variations of the effective average hygroscopicity parameter for CCN-active particles (κa) could be parameterized as a function of organic and inorganic mass fractions (forg, finorg) determined by the AMS: κa,p=κorg·forg + κinorg·finorg. The characteristic κ values of organic and inorganic components were similar to those observed in other continental regions of the world: κorg≈0.1 and κinorg≈0.6. The campaign average κa values increased with particle size from ~0.25 at ~50 nm to ~0.4 at ~200 nm, while forg decreased with particle size. At ~50 nm, forg was on average 60% and increased to almost 100% during a biomass burning event. The VTDMA results and complementary aerosol optical data suggest that the large fractions of CCN-inactive particles observed at low supersaturations (up to 60% at S≤0.27%) were externally mixed weakly CCN-active soot particles with low volatility (diameter reduction &lt;5% at 300 °C) and effective hygroscopicity parameters around κLV≈0.01. A proxy for the effective average hygroscopicity of the total ensemble of CCN-active particles including weakly CCN-active particles (κt) could be parameterized as a function of κa,p and the number fraction of low volatility particles determined by VTDMA (φLV): κt,p=κa,p−φLV·(κa,p−κLV). Based on κ values derived from AMS and VTDMA data, the observed CCN number concentrations (NCCN,S≈102–104 cm−3 at S = 0.068–0.47%) could be efficiently predicted from the measured particle number size distribution. The mean relative deviations between observed and predicted CCN concentrations were ~10% when using κt,p, and they increased to ~20% when using only κa,p. The mean relative deviations were not higher (~20%) when using an approximate continental average value of κ≈0.3, although the constant κ value cannot account for the observed temporal variations in particle composition and mixing state (diurnal cycles and biomass burning events). Overall, the results confirm that on a global and climate modeling scale an average value of κ≈0.3 can be used for approximate predictions of CCN number concentrations in continental boundary layer air when aerosol size distribution data are available without information about chemical composition. Bulk or size-resolved data on aerosol chemical composition enable improved CCN predictions resolving regional and temporal variations, but the composition data need to be highly accurate and complemented by information about particle mixing state to achieve high precision (relative deviations &lt;20%).

Article

Cloud condensation nuclei in polluted air and biomass burning smoke near the mega-city Guangzhou, China – Part 2: Size-resolved aerosol chemical composition,  diurnal cycles, and externally mixed weakly CCN-active soot particles