Browsing by Author "Ravindra N. Singh"

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Adaptation to Variable Environments, Resilience to Climate Change: Investigating land, water and settlement in Indus northwest India
(University of Chicago Press, 2017) Cameron A. Petrie; Ravindra N. Singh; Jennifer Bates; Yama Dixit; Charly A. I. French; David A. Hodell; Penelope J. Jones; Carla Lancelotti; Frank Lynam; Sayantani Neogi; Arun K. Pandey; Danika Parikh; Vikas Pawar; David I. Redhouse; Dheerendra P. Singh
This paper explores the nature and dynamics of adaptation and resilience in the face of a diverse and varied environmental and ecological context using the case study of South Asia’s Indus Civilization (ca. 3000–1300 BC). Most early complex societies developed in regions where the climatic parameters faced by ancient subsistence farmers were varied but rain falls primarily in one season. In contrast, the Indus Civilization developed in a specific environmental context that spanned a very distinct environmental threshold, where winter and summer rainfall systems overlap. There is now evidence to show that this region was directly subject to climate change during the period when the Indus Civilization was at its height (ca. 2500–1900 BC). The Indus Civilization, therefore, provides a unique opportunity to understand how an ancient society coped with diverse and varied ecologies and change in the fundamental environmental parameters. This paper integrates research carried out as part of the Land, Water and Settlement project in northwest India between 2007 and 2014. Although coming from only one of the regions occupied by Indus populations, these data necessitate the reconsideration of several prevailing views about the Indus Civilization as a whole and invigorate discussion about human-environment interactions and their relationship to processes of cultural transformation. © 2017 by The Wenner-Gren Foundation for Anthropological Research. All rights reserved.
Correction to: Cereals, calories and change: exploring approaches to quantification in Indus archaeobotany (Archaeological and Anthropological Sciences, (2018), 10, 7, (1703-1716), 10.1007/s12520-017-0489-2)
(Springer Verlag, 2019) Jennifer Bates; Cameron A. Petrie; Ravindra N. Singh
The original version of this article, unfortunately, contained an error. An acknowledgement of funding was incomplete. The acknowledgements have been updated and now read as followed: This research was carried out as a part of J. Bates’s PhD research, which was funded by the Arts and Humanities Research Council. Analysis was carried out in the George Pitt Rivers laboratory in the McDonald Institute for Archaeological Research, University of Cambridge. Samples were provided by the Land, Water, Settlement project, co-directed by C.A. Petrie and R.N. Singh, which is a collaboration between the University of Cambridge and Banaras Hindu University that was carried out with the support of the Archaeological Survey of India. The Land, Water, Settlement project was funded by the UK India Education Research Initiative, British Academy Stein Arnold Fund, Isaac Newton Trust, McDonald Institute for Archaeological Research and the Research Councils UK. The contribution made by C.A. Petrie was supported by funding from the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme (grant agreement no 648609). Additional fieldwork funding for J. Bates was provided by the Arts and Humanities Research Council, Rouse-Ball Research Fund, Cambridge India Partnership Fund, Division of Archaeology Fieldwork Fund and Trinity College Projects Fund. The authors would also like to thank Prof. Martin Jones, Prof. Dorian Fuller, Prof. Marco Madella, Dr. Michèle Wollstonecroft and Dr. Rachel Ballantyne for their advice and help. © 2018, Springer-Verlag GmbH Germany, part of Springer Nature.
CORROSION STUDIES OF ZINC IN AQUEOUS BINARY MIXTURES OF ACETONITRILE THROUGH POLARISATION TECHNIQUE.
(1987) L. Bahadur; P. Singh; Ravindra N. Singh
The nature of cathodic and anodic polarisation curves is the indicative of the fact that the corrosion of zinc in the present system is cathodically controlled. With an increase in acetonitrile content in the mixture cathodic polarisation curves at first shift towards higher current density and then after a particular acetonitrile content the shift is in reverse direction. The anodic polarisation curves shift in oscillatory manner with increasing acetonitrile content in the solvent mixture. The passivity is altogether absent in the anodic curves for all the representative concentrations. Stirring of the medium leads to the enhancement in corrosion rate. Accelerated weight loss measurement at a fixed potential shows a linear increase in weight loss with polarisation time.
CORROSION STUDIES OF ZINC IN AQUEOUS BINARY MIXTURES OF ACETONITRILE THROUGH POLARISATION TECHNIQUE.
(1987) L. Bahadur; P. Singh; Ravindra N. Singh
The nature of cathodic and anodic polarisation curves is indicative of the fact that the corrosion of zinc in the present system is cathodically controlled. With an increase in acetonitrile content in the mixture cathodic polarisation curves at first shift towards higher current density and then after particular acetonitrile content the shift is in reverse direction. The anodic polarisation curves shift in oscillatory manner with increasing acetonitrile content in the solvent mixture. The passivity is altogether absent in the anodic curves for all the representative concentrations. Stirring of the medium leads to the enhancement in corrosion rate. Accelerated weight loss measurement at a fixed potential shows a linear increase in weight loss with polarisation time.
Electrochemical behaviour of brass (Cu/Zn, 63/37) in binary mixtures of acetonitrile and water
(1987) Ravindra N. Singh; Lal Bahadur; Padma Singh
Electrochemical behaviour of commercial brass, 63/37 (Cu/Zn) in acetonitrile (AN) and water mixtures of varying compositions (ie 2-100 m/o AN) at 30°C has been studied using accelerated weight loss method, solution analysis and potentiostatic polarization technique. It is found that during anodic polarization brass exhibits an active-passive transition in 2, 5, 10, 2o and 30 m/o AN, while no passivity has been observed in 50, 70, 95 and 100 m/o AN. Further the dissolution of brass has been found to be cathodically controlled. The open-circuit potential measurements show that as AN content in the solvent mixture increases, both immersion as well as steady potentials gradually shift towards less noble direction. The weight loss and solution analysis show preferential dissolution of zinc in the initial stages which progressively decreases with time. © 1987.
Electrochemical corrosion behaviour of copper in binary mixtures of dimethylformamide and water
(1988) Ravindra N. Singh; Padma Singh; Wairokpam R. Singh
The results of electrochemical corrosion studies of copper in dimethylformamide and water mixtures show that the corrosion of copper is cathodically controlled with the metal being anodically active in the region of a higher mole percent of water. It is interesting to note that polarization curves determined in aerated mixtures do not show passivity, while in deaerated mixtures they show passivity in 30, 50, 70, 90, and 100 mol% DMF. Stirring and the dissolved oxygen influence both cathodic and anodic processes.
Electrochemical Studies on Protective Thin Co3O4 and NiCo2O4 Films Prepared on Titanium by Spray Pyrolysis for Oxygen Evolution
(1990) Ravindra N. Singh; J.-F. Koenig; G. Poillerat; P. Chartier
Electrochemical studies were done on thin Co3O4 and NiCo2O4 films on Ti by cyclic voltammetric and potentiostatic polarization techniques. The films were quite conductive and prevented the underlying surface from playing a harmful role during measurements. The results indicated the formation of a surface quasi-reversible redox couple, CoIV/CoIII, in KOH solution. The reaction order with respect to OH− ion concentration was found to be nearly 2. The Tafel slopes decreased with increasing KOH concentrations. NiCo2O4 was observed to evolve oxygen gas at a lower overpotential as compared to that of Co3O4. Electrode kinetic parameters suggest similar mechanisms for the oxygen evolution for both the oxides. © 1990, The Electrochemical Society, Inc. All rights reserved.
Erratum to: Intensified summer monsoon and the urbanization of Indus Civilization in northwest India (Scientific Reports, (2018), 8, 1, (4225), 10.1038/s41598-018-22504-5)
(Nature Publishing Group, 2018) Yama Dixit; David A. Hodell; Alena Giesche; Sampat K. Tandon; Fernando Gázquez; Hari S. Saini; Luke C. Skinner; Syed A. I. Mujtaba; Vikas Pawar; Ravindra N. Singh; Cameron A. Petrie
A correction to this article has been published and is linked from the HTML and PDF versions of this paper. The error has not been fixed in the paper. © 2018, The Author(s).
Geoarchaeological insights into the location of Indus settlements on the plains of northwest India
(Cambridge University Press, 2020) Sayantani Neogi; Charles A.I. French; Julie A. Durcan; Ravindra N. Singh; Cameron A. Petrie
This article presents a geomorphological and micromorphological study of the locational context of four Indus civilisation archaeological sites - Alamgirpur, Masudpur I and VII, and Burj - all situated on the Sutlej-Yamuna interfluve in northwest India. The analysis indicates a strong correlation between settlement foundation and particular landscape positions on an extensive alluvial floodplain. Each of the analysed sites was located on sandy levees and/or riverbank deposits associated with former channels. These landscape positions would have situated settlements above the level of seasonal floodwater resulting from the Indian summer monsoon. In addition, the sandy soils on the margins of these elevated landscape positions would have been seasonally replenished with water, silt, clay, and fine organic matter, considerably enhancing their capacity for water retention and fertility and making them particularly suitable for agriculture. These former landscapes are obscured by recent modification and extensive agricultural practices. These geoarchaeological evaluations indicate that there is a hidden landscape context for each Indus settlement. This specific type of interaction between humans and their local context is an important aspect of Indus cultural adaptations to diverse, variable, and changing environments. © Copyright University of Washington. Published by Cambridge University Press, 2019.
Holocene landscape dynamics in the Ghaggar-Hakra palaeochannel region at the northern edge of the Thar Desert, northwest India
(Elsevier Ltd, 2019) Julie A. Durcan; David S.G. Thomas; Sanjeev Gupta; Vikas Pawar; Ravindra N. Singh; Cameron A. Petrie
Precession-forced change in insolation has driven de-intensification of the Asian Monsoon systems during the Holocene. Set against this backdrop of a weakening monsoon, Indus Civilisation populations occupied a number of urban settlements on the Ghaggar-Hakra plains during the mid-Holocene from 4.5 ka until they were abandoned by around 3.9 ka. Regional climatic variability has long been cited as a potential factor in the transformation of Indus society, however there remain substantial gaps in the chronological framework for regional climatic and environmental change at the northern margin of the Thar Desert. This makes establishing a link between climate, environment and society challenging. This paper presents 24 optically stimulated luminescence ages from a mixture of 11 fluvial and aeolian sedimentological sites on the Ghaggar-Hakra floodplain/interfluve, an area which was apparently densely populated during the Indus urban phase and subsequently. These ages identify fluvial deposition which mostly pre-dates 5 ka, although fluvial deposits are detected in the Ghaggar palaeochannel at 3.8 ka and 3.0 ka, post-dating the decline of urbanism. Aeolian accumulation phases occur around 9 ka, 6.5 ka, 2.8 ka and 1.7 ka. There is no clear link to a 4.2 ka abrupt climate event, nor is there a simple switch between dominant fluvial deposition and aeolian accumulation, and instead the OSL ages reported present a view of a highly dynamic geomorphic system during the Holocene. The decline of Indus urbanism was not spatially or temporally instantaneous, and this paper suggests that the same can be said for the geomorphic response of the northern Thar to regional climate change. © 2017 Elsevier Ltd and INQUA
How to 'downsize' a complex society: An agent-based modelling approach to assess the resilience of Indus Civilisation settlements to past climate change
(IOP Publishing Ltd, 2020) Andreas Angourakis; Jennifer Bates; Jean-Philippe Baudouin; Alena Giesche; M. Cemre Ustunkaya; Nathan Wright; Ravindra N. Singh; Cameron A. Petrie
The development, floruit and decline of the urban phase of the Indus Civilisation (c.2600/2500-1900 BC) provide an ideal opportunity to investigate social resilience and transformation in relation to a variable climate. The Indus Civilisation extended over most of the Indus River Basin, which includes a mix of diverse environments conditioned, among other factors, by partially overlapping patterns of winter and summer precipitation. These patterns likely changed towards the end of the urban phase (4.2 ka BP event), increasing aridity. The impact of this change appears to have varied at different cities and between urban and rural contexts. We present a simulation approach using agent-based modelling to address the potential diversity of agricultural strategies adopted by Indus settlements in different socio-ecological scenarios in Haryana, NW India. This is an ongoing initiative that consists of creating a modular model, Indus Village, that assesses the implications of trends in cropping strategies for the sustainability of settlements and the resilience of such strategies under different regimes of precipitation. The model aims to simulate rural settlements structured into farming households, with sub-models representing weather and land systems, food economy, demography, and land use. This model building is being carried out as part of the multi-disciplinary TwoRains project. It brings together research on material culture, settlement distribution, food production and consumption, vegetation and paleoenvironmental conditions. © 2020 The Author(s). Published by IOP Publishing Ltd
INFLUENCE OF MINOR ADDITIONS OF TA AND ND ON THE CORROSION BEHAVIOUR OF PROPELLER BRONZE IN MINERAL ACIDS.
(1988) Ravindra N. Singh; S.K. Tiwari; N. Verma
The influence of minor additions of Ta and Nd on the corrosion behavior of propeller bronze (82% Cu, 9% Al, 4% Ni, 4% Fe, 1% Mn) in 4% HCl, 1% HNO//3 and 1. 7% H//2SO//4 has been investigated using weight loss and potentiostatic polarization techniques. Addition of both Ta and Nd reduces the corrosion resistance in HCl and HNO//3 solutions and increases resistance in H//2SO//4 solution. The effect of these additions on some other properties such as hardness, tensile strength, percentage elongation and forgeability has also been observed.
Intensified summer monsoon and the urbanization of Indus Civilization in northwest India
(Nature Publishing Group, 2018) Yama Dixit; David A. Hodell; Alena Giesche; Sampat K. Tandon; Fernando Gázquez; Hari S. Saini; Luke C. Skinner; Syed A. I. Mujtaba; Vikas Pawar; Ravindra N. Singh; Cameron A. Petrie
Today the desert margins of northwest India are dry and unable to support large populations, but were densely occupied by the populations of the Indus Civilization during the middle to late Holocene. The hydroclimatic conditions under which Indus urbanization took place, which was marked by a period of expanded settlement into the Thar Desert margins, remains poorly understood. We measured the isotopic values (δ18O and δD) of gypsum hydration water in paleolake Karsandi sediments in northern Rajasthan to infer past changes in lake hydrology, which is sensitive to changing amounts of precipitation and evaporation. Our record reveals that relatively wet conditions prevailed at the northern edge of Rajasthan from ~5.1 ± 0.2 ka BP, during the beginning of the agricultural-based Early Harappan phase of the Indus Civilization. Monsoon rainfall intensified further between 5.0 and 4.4 ka BP, during the period when Indus urban centres developed in the western Thar Desert margin and on the plains of Haryana to its north. Drier conditions set in sometime after 4.4 ka BP, and by ~3.9 ka BP an eastward shift of populations had occurred. Our findings provide evidence that climate change was associated with both the expansion and contraction of Indus urbanism along the desert margin in northwest India. © 2018 The Author(s).
Journey to the east: Diverse routes and variable flowering times for wheat and barley en route to prehistoric China
(Public Library of Science, 2017) Xinyi Liu; Diane L. Lister; Zhijun Zhao; Cameron A. Petrie; Xiongsheng Zeng; Penelope J. Jones; Richard A. Staff; Anil K. Pokharia; Jennifer Bates; Ravindra N. Singh; Steven A. Weber; Giedre Motuzaite Matuzeviciute; Guanghui Dong; Haiming Li; Hongliang Lü; Hongen Jiang; Jianxin Wang; Jian Ma; Duo Tian; Guiyun Jin; Liping Zhou; Xiaohong Wu; Martin K. Jones
Today, farmers in many regions of eastern Asia sow their barley grains in the spring and harvest them in the autumn of the same year (spring barley). However, when it was first domesticated in southwest Asia, barley was grown between the autumn and subsequent spring (winter barley), to complete their life cycles before the summer drought. The question of when the eastern barley shifted from the original winter habit to flexible growing schedules is of significance in terms of understanding its spread. This article investigates when barley cultivation dispersed from southwest Asia to regions of eastern Asia and how the eastern spring barley evolved in this context. We report 70 new radiocarbon measurements obtained directly from barley grains recovered from archaeological sites in eastern Eurasia. Our results indicate that the eastern dispersals of wheat and barley were distinct in both space and time. We infer that barley had been cultivated in a range of markedly contrasting environments by the second millennium BC. In this context, we consider the distribution of known haplotypes of a flowering-time gene in barley, Ppd-H1, and infer that the distributions of those haplotypes may reflect the early dispersal of barley. These patterns of dispersal resonate with the second and first millennia BC textual records documenting sowing and harvesting times for barley in central/eastern China. © 2017 Liu et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
KINETICS AND MECHANISM OF DECOMPOSITION OF HYDROGEN PEROXIDE CATALYSED BY Cu**2** plus ADSORBED ON BERYLLIUM OXIDE.
(1987) S.K. Tiwari; Ravindra N. Singh
The rate of decomposition of H//2O//2 at 30 degree C, catalysed by Cu**2** plus ions adsorbed on beryllium oxide has been found to be first-order with respect to left bracket H//2O//2 right bracket . As the amount of surface adsorbed ions increases from 0. 95 to 9. 55 mg for a fixed amount of BeO (0. 5 g), the value of first-order rate constant initially increases linearly, reaches a maximum and decreases considerably and finally becomes constant. It is further found that with the increase in pH of the reaction medium from 7. 2 to 8. 7, the rate of decomposition of H//2O//2, which initially increases almost linearly, gets accelerated sharply after pH 8. 4. A probable reaction mechanism for the decomposition of H//2O//2 consistent with kinetic data has been suggested.
Lipid residues in pottery from the Indus Civilisation in northwest India
(Elsevier Inc., 2021) Akshyeta Suryanarayan; Miriam Cubas; Oliver E. Craig; Carl P. Heron; Vasant S. Shinde; Ravindra N. Singh; Tamsin C. O'Connell; Cameron A. Petrie
This paper presents novel insights into the archaeology of food in ancient South Asia by using lipid residue analysis to investigate what kinds of foodstuffs were used in ceramic vessels by populations of the Indus Civilisation in northwest India. It examines how vessels were used in urban and rural Indus settlements during the Mature Harappan period (c.2600/2500–1900 BC), the relationship between vessels and the products within them, and identifies whether changes in vessel use occurred from the Mature Harappan to Late Harappan periods, particularly during climatic instability after 4.2 ka BP (c.2100 BC). Despite low lipid concentrations, which highlight challenges with conducting residue analysis in arid, seasonally-wet and alkaline environments, 71% of the vessels yielded appreciable quantities of lipid. Lipid profiles revealed the use of animal fats in vessels, and contradictory to faunal evidence, a dominance of non-ruminant fats, with limited evidence of dairy processing. The absence of local modern reference fats makes this dataset challenging to interpret, and it is possible that plant products or mixtures of plant and animal products have led to ambiguous fatty acid-specific isotopic values. At the same time, it appears that urban and rural populations processed similar types of products in vessels, with limited evidence for change in vessel use from the urban to the post-urban period. This study is a systematic investigation into pot lipid residues from multiple sites, demonstrating the potential of the method for examining ancient Indus foodways and the need for the development of further research in ancient organic residues in South Asia. © 2020 The Authors
Low-temperature synthesis of perovskite-type oxides of lanthanum and cobalt and their electrocatalytic properties for oxygen evolution in alkaline solutions
(1995) Amar N. Jain; Shashi K. Tiwari; Ravindra N. Singh; Pierre Chartier
A new hydroxide-solid-solution precursor route has been employed to synthesize perovskite-type oxides of lanthanum and cobalt at 500 °C. The oxide powders were used to obtain thin films on nicket supports by painting with a slurry of the oxide followed by sintering at 400 °C. The films were satisfactorily adherent and porous. They have been observed to exhibit p-type semiconducting behaviour in the potential region -50 to +300 mV in 1 mol I-1 KOH. Cyclic voltametric study indicated the formation of a diffusion-controlled quasi-reversible redox couple (E°= 417 mV) prior to the onset of O2 evolution at the oxide surface. It was found that Sr (or Ca) substitution enhanced greatly both the electrochemically active area as well the apparent electrocatalytic activity. The oxygen evolution reaction followed approximately first-order kinetics in OH- concentration, regardless of the nature of cobaltates. Values of the Tafel slope were 65 ± 5 mV decade-1 up to a current density of ca. 100 mA cm-2. Sr- (or Ca-) substituted cobaltates were more active for oxygen evolution than those prepared by other methods.
Mapping archaeology while mapping an empire: Using historical maps to reconstruct ancient settlement landscapes in modern India and Pakistan
(MDPI AG, 2019) Cameron A. Petrie; Hector A. Orengo; Adam S. Green; Joanna R. Walker; Arnau Garcia; Francesc Conesa; J. Robert Knox; Ravindra N. Singh
A range of data sources are now used to support the process of archaeological prospection, including remote sensed imagery, spy satellite photographs and aerial photographs. This paper advocates the value and importance of a hitherto under-utilised historical mapping resource—the Survey of India 1” to 1-mile map series, which was based on surveys started in the mid–late nineteenth century, and published progressively from the early twentieth century AD. These maps present a systematic documentation of the topography of the British dominions in the South Asian Subcontinent. Incidentally, they also documented the locations, the height and area of thousands of elevated mounds that were visible in the landscape at the time that the surveys were carried out, but have typically since been either damaged or destroyed by the expansion of irrigation agriculture and urbanism. Subsequent reanalysis has revealed that many of these mounds were actually the remains of ancient settlements. The digitisation and analysis of these historic maps thus creates a unique opportunity for gaining insight into the landscape archaeology of South Asia. This paper reviews the context within which these historical maps were created, presents a method for georeferencing them, and reviews the symbology that was used to represent elevated mound features that have the potential to be archaeological sites. This paper should be read in conjunction with the paper by Arnau Garcia et al. in the same issue of Geosciences, which implements a research programme combining historical maps and a range of remote sensing approaches to reconstruct historical landscape dynamics in the Indus River Basin. © 2018 by the authors. Licensee MDPI, Basel, Switzerland.
Nanocomposites of nitrogen-doped graphene and cobalt tungsten oxide as efficient electrode materials for application in electrochemical devices
(AIMS Press, 2016) Nirmala Kumari; Ravindra N. Singh
Nitrogen-doped graphene (N-GNS), cobalt tungsten oxide (CoWO4) and their binary composites have been synthesized and their structural and electrochemical and surface properties were investigated for application as electrode materials for oxygen reduction reaction (ORR) as well as super capacitors in 1 M KOH at 25 °C. Result shows that the composite, 40%CoWO4/N-GNS, has greatly enhanced capacitance as well as retention capacity, compared to its constituent compounds, N-GNS and CoWO4. The ORR activity and stability of the composite are also found to be much superior to N-GNS (or CoWO4) under similar conditions. The 40%CoWO4/N-GNS catalyst has also exhibited reasonably good catalytic activity for oxygen evolution reaction (OER) while that the NGNS electrode was practically inactive. © 2016 Ravindra N. Singh, et al.
Re-discovering ancient landscapes: Archaeological survey of mound features from historical maps in northwest india and implications for investigating the large-scale distribution of cultural heritage sites in South Asia
(MDPI AG, 2019) Adam S. Green; Hector A. Orengo; Aftab Alam; Arnau Garcia-Molsosa; Lillian M. Green; Francesc Conesa; Amit Ranjan; Ravindra N. Singh; Cameron A. Petrie
Incomplete datasets curtail the ability of archaeologists to investigate ancient landscapes, and there are archaeological sites whose locations remain unknown in many parts of the world. To address this problem, we need additional sources of site location data. While remote sensing data can often be used to address this challenge, it is enhanced when integrated with the spatial data found in old and sometimes forgotten sources. The Survey of India 1" to 1-mile maps from the early twentieth century are one such dataset. These maps documented the location of many cultural heritage sites throughout South Asia, including the locations of numerous mound features. An initial study georeferenced a sample of these maps covering northwest India and extracted the location of many potential archaeological sites-historical map mound features. Although numerous historical map mound features were recorded, it was unknown whether these locations corresponded to extant archaeological sites. This article presents the results of archaeological surveys that visited the locations of a sample of these historical map mound features. These surveys revealed which features are associated with extant archaeological sites, which were other kinds of landscape features, and which may represent archaeological mounds that have been destroyed since the maps were completed nearly a century ago. Their results suggest that there remain many unreported cultural heritage sites on the plains of northwest India and the mound features recorded on these maps best correlate with older archaeological sites. They also highlight other possible changes in the large-scale and long-term distribution of settlements in the region. The article concludes that northwest India has witnessed profound changes in its ancient settlement landscapes, creating in a long-term sequence of landscapes that link the past to the present and create a foundation for future research and preservation initiatives. © 2019 by the authors.