Faculty Publications
Permanent URI for this communityhttps://idr.nitk.ac.in/handle/123456789/18736
Publications by NITK Faculty
Browse
10 results
Search Results
Item Case study of a hybrid (Wind and solar) power plant(2011) Jaralikar, S.M.; Mangalpady, M.The paper highlights the urgency of utilizing and promoting use of non conventional sources, particularly the wind and solar energy, so as to control the environmental pollution, such as ozone layer depletion, deforestation, loss of biodiversity, global warming etc. As a case study, the various performance factors of a 10 kW hybrid (wind and solar) power plant, which is having 60:40 power generation share of wind power to solar power were analysed. The study shows that there is mismatch between the designed and actual plant load factor (PLF), as well as the power generation share of the wind and solar power plant. It was also found that the plant utilization factor (PUF) was poor and that there is very less scope for installation of solar tracking system. Based on the detailed analysis of obtained results, certain recommendations were made for streamlining and optimizing the power generation capacity, and also for better utilization of generated power.Item Characterization and performance of processed lateritic fine aggregates in cement mortars and concretes(Elsevier Ltd, 2019) Yaragal, S.C.; Basavana Gowda, S.N.; C, C.Availability of river sand is becoming scarce, due to rapid increase in infrastructure projects in India. Acute shortage of river sand, has led to indiscriminate sand mining. Adverse effect of sand mining includes river bank erosion, river bed degradation, loss of biodiversity and deterioration of river water quality and ground water availability. To address the above issues, research efforts are on, to find substitutes for river sand to be used as fine aggregate in mortars and concretes. One among the locally available resources is laterite. Laterite is a product of tropical or sub-tropical weathering, which is an abundant soil material in many parts of India. An attempt has been made to characterize the processing technique to obtain good quality lateritic fine aggregates (lateritic FA). Experiments were designed and conducted to study the performance of lateritic FA as replacement to river sand, in cement mortars and concretes. Processed lateritic FA in replacement levels of 0, 25, 50, 75 and 100 wt% to river sand at all fineness levels (Zone I to Zone IV as per Indian standards) is considered. Microstructure studies were conducted to understand the arrangement of river sand and lateritic FA with cement matrix and their Interfacial Transition Zones (ITZ) using Scanning Electron Microscope (SEM). The workability and compressive strength characteristics of cement mortars and concretes are evaluated. Laterized mortars with Zone III and Zone IV fine aggregates, at all replacement levels, result in the same compressive strengths as those of control mortars. Suitable strength enhancement technique has been attempted to achieve strengths of Zone I and Zone II lateritic fine aggregates based mortars at 100 wt% replacement, to achieve strength at least equal to or more than those of control mortars. Laterized concretes have achieved nearly the same strengths as those of control concretes, at all replacement levels and for all fineness levels (Zone I to Zone IV). © 2018 Elsevier LtdItem Public expenditure effectiveness for biodiversity conservation: Understanding the trends for project tiger in India(Now Publishers Inc, 2020) Nayak, B.P.; Jena, P.R.; Chaudhury, S.Project Tiger, a flagship programme for conservation of the tiger launched in 1973 in India has expanded over the years in terms of its geographical coverage and volume of expenditure. However, the tiger is still an endangered species in India and conservation efforts face multiple challenges like widespread loss of tiger habitat, decline in the density of prey animals, illegal poaching, human-animal conflicts and revenge killing. This study explores the trends and patterns of government expenditure over the years by reviewing the annual plan of operation of different tiger reserves and examines whether the volume or the pattern of expenditure has any relationship with performance, measured by the change in the number of tigers and occupancy in 28 tiger reserves. Analysis of the financial outlay data in the Annual Plan of Operation of the tiger reserves suggest that habitat improvement, which includes relocation, gets the highest share whereas human-animal conflict and eco-development gets the least, though more than 0.5 million households are located in and around the tiger reserves 0.3 million. Allocations are neither proportional to the size of the reserve nor to the tiger population. The relationships between expenditure categories and tiger populations are explored through a negative binomial regression model. Among the expenditure categories, expenditure on habitat improvement, excluding relocation, is found to be negatively related to tiger population whereas all other expenditures like infrastructure, protection, and human-animal conflict are positively related. © 2020 B. P. Nayak and P. R. Jena and S. ChaudhuryItem Evaluating the effects of forest fire on water balance using fire susceptibility maps(Elsevier B.V., 2020) Venkatesh, K.; Konkathi, K.; Ramesh, H.Sudden and long term changes in the landscape can be attributed to periodic wildfires which, is a cyclic occurrence at Kudremukh national forest in Western Ghats of India. These land-use changes influence the hydrology of landscape, causing disintegration of soil, loss of biodiversity, changes in stream and flooding. To understand and account for these land-use changes, a new approach was implemented by developing fire susceptibility map from topographic, climatic and human-induced factors and validating it with MODIS (Moderate-resolution Imaging Spectro-radiometer) fire points for discretising accuracy. The fire susceptibility map can be used for studying the long-term (year or more) effects of fire on water balance systems. The fire susceptibility map generated for the years 2005 and 2017 was overlaid with MODIS LULC (Land Use Land Cover) for establishing the post-fire scenario whereas MODIS LULC MCD12Q1 (2005 and 2017) was considered as the no-fire scenario to analyse the intensity of the fire and its effect on streamflow and infiltration. These maps along with historical satellite hydro-climatic datasets, were used to assess the effect of forest fire on hydrological parameters using the SWAT (Soil and Water Assessment Tool) model. No-fire and post-fire conditions were established by modifying SCS-CN (Soil Conservation Service-Curve Number) based on previous works of literature to represent the catchment as unburnt and burnt area. The SWAT model was calibrated (2002–2008) and validated (2009–2012) for establishing a baseline scenario. The sensitive parameters obtained from SUFI-2 (Sequential Uncertainty Fitting) algorithm in SWAT-CUP (Calibration and Uncertainty Programs) were used to simulate stream flows till 2017 due to lack of observed streamflow data for the year 2017. It was inferred that the effect of wildfire on flows in recent years (2017) had increased radically when compared to the flows before a decade (2005), diminishing the rate of infiltration and causing the deficit in groundwater to energise. The methodology can further be executed in any forest area for distinguishing fire hazard zones and implementing prior actions in those areas for mitigation of forest fires and maintaining sustainable water balance. © 2019 Elsevier LtdItem Adsorption of selective fluoroquinolones by cysteine modified silane magnetic nanocomposite from the aqueous phase(Institute for Ionics, 2023) Senathiraja, T.; Lolla, S.A.; Singh, Y.; Kollarahithlu, S.C.; Mohan Balakrishnan, R.M.Elevated levels of pharmaceutical pollutants in the aquatic environment have caused detrimental effects on water quality and biodiversity. Nanomaterials are among the most promising technologies to detect, adsorb, and remove these pollutants from the aqueous systems. The current work explores the applicability of nickel ferrite nanocomposite functionalized with L-cysteine attached 3-glycidyloxypropyltrimethoxysilane to remove a selective class of antibiotics known as fluoroquinolones (Lomefloxacin, Ciprofloxacin, and Norfloxacin). 20 mg of this nanocomposite achieve maximum removal efficiencies of 61%, 67%, and 75% for 40 mg L−1 of lomefloxacin, norfloxacin, and ciprofloxacin, respectively. The nanocomposites also show good regeneration capacity with negligible reduction in the efficiencies up to three cycles. Furthermore, adsorption isotherms such as Langmuir and Freundlich isotherms were used to characterize the removal of fluoroquinolones from the aqueous phase by the nanocomposites. The results show that the adsorption process was in good agreement with the Langmuir isotherm, thus confirming its monolayer sorption process and also reveals that adsorption kinetics follows a pseudo-second-order model. The maximum adsorption capacity of functionalized nickel ferrite nanocomposites are 122 mg g−1, 135 mg g−1, and 150 mg g−1 for lomefloxacin, norfloxacin, and ciprofloxacin, respectively. Overall, all the results obtained indicate that the nickel ferrite nanocomposite functionalized with L-cysteine attached 3-glycidyloxypropyltrimethoxysilane is an effective adsorbent to remove fluoroquinolones from the aqueous systems and could be potentially incorporated in water treatment processes under well-defined parameters. © 2022, The Author(s) under exclusive licence to Iranian Society of Environmentalists (IRSEN) and Science and Research Branch, Islamic Azad University.Item Assessing forest health using remote sensing-based indicators and fuzzy analytic hierarchy process in Valmiki Tiger Reserve, India(Institute for Ionics, 2023) Roshani; Sajjad, H.; Rahaman, M.H.; Rehman, S.; Masroor, M.; Ahmed, R.Anthropogenic activities, climate variability and environmental stresses have greatly affected forest ecosystems globally. Thus, monitoring of forest health is essential for proper planning and effective management. The present study employed an integrated approach of remote sensing and fuzzy analytic hierarchy process to assess the forest health in the Valmiki Tiger Reserve in India. Advanced vegetation index, normalized difference vegetation index, normalized difference moisture index, forest fragmentation, rainfall and soil types were derived from remote sensing data. Multiple buffer zones of villages, roads, railways and canals were also determined for analyzing the forest health status. These layers were prepared in the geographical information system. These layers were given weightage using fuzzy analytic hierarchy process. These layers were integrated to prepare forest health map using weighted overlay method. The results revealed that the largest forest area was found under moderately healthy forest (37%) followed by healthy forest (31%) and unhealthy forest (13%). Of the total area of the Reserve, 19% area was under non-forest category. Human-induced disturbances such as encroachment, illegal sand mining, livestock grazing and forest conversion to agriculture have been attributed to the unhealthy forest in the Reserve. The receiver operating characteristic curve value and area under curve (0.792) show reliability of forest health map. The findings of this study may be helpful for forest managers, conservationists and local communities in devising sustainable strategies for effective management of the forest. The methodological framework adopted in this study may be utilized in other geographical regions interested in assessing forest health. © 2022, The Author(s) under exclusive licence to Iranian Society of Environmentalists (IRSEN) and Science and Research Branch, Islamic Azad University.Item Extraction and characterization of lignin from waste invasive weeds with dioxane-based process(Springer Science and Business Media Deutschland GmbH, 2023) Borah, A.J.; Dikshit, P.K.; Doloi, M.; Moholkar, V.S.; Poddar, M.K.This study has put forth the concept of “control through utilization” for invasive weeds, which cause severe damage to ecosystem and biodiversity. The study comprised of extraction of lignin and pretreatment of spent biomass of four invasive weeds. Lignin was extracted from native biomass using 1,4–dioxane as solvent. Lignin yield of all biomass varied in the range 8.61 − 11.14% w/w with the solvent recovery of 75.56–78.88% v/v. Extracted lignin was characterized using FTIR, TGA, and GPC. Lignin from Mikania micrantha had the highest thermal stability (T50% = 490 °C) and molecular weight (Mw = 5537 g/mol). The spent biomass was subjected to dilute acid pretreatment for synthesis of total reducing sugars (TRS). TRS yields from different entities were as follows: non-extracted biomass = 94.18 − 221.81 mg/g, warm water wash = 8.74 − 15.66 mg/g, and raw biomass = 115.9 − 391.27 mg/g raw biomass. Biomass of Saccharum spontaneum gave the highest TRS yield. Graphical abstract: [Figure not available: see fulltext.] © 2021, The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.Item Spatio-temporal classification of land use and land cover and its changes in Kerala using remote sensing and machine learning approach(Springer Science and Business Media Deutschland GmbH, 2024) Vijay, A.; Varija, K.Land use and land cover (LULC) analysis gives important information on how the region has evolved over time. Kerala, a land with an extensive and dynamic history of land-use changes, has, until now, lacked comprehensive investigations into this history. So the current study focuses on Kerala, one of the ecologically diverse states in India with complex topography, through Landsat images taken from 1990 to 2020 using two different machine learning classifications, random forest (RF) and classification and regression trees (CART) on Google Earth Engine (GEE) platform. RF and CART are versatile machine learning algorithms frequently employed for classification and regression, offering effective tools for predictive modelling across diverse domains due to their flexibility and data-handling capabilities. Normalised Difference Vegetation Index (NDVI), Normalised Differences Built-up Index (NDBI), Modified Normalised Difference Water Index (MNDWI), and Bare soil index (BSI) are integral indices utilised to enhance the precision of land use and land cover classification in satellite imagery, playing a crucial role by providing valuable insights into specific landscape attributes that may be challenging to identify using individual spectral bands alone. The results showed that the performance of RF is better than that of CART in all the years. Thus, RF algorithm outputs are used to infer the change in the LULC for three decades. The changes in the NDVI values point out the loss of vegetation for the urban area expansion during the study period. The increasing value of NDBI and BSI in the state indicates growth in high-density built-up areas and barren land. The slight reduction in the value of MNDWI indicates the shrinking water bodies in the state. The results of LULC showed the urban expansion (158.2%) and loss of agricultural area (15.52%) in the region during the study period. It was noted the area of the barren class, as well as the water class, decreased steadily from 1990 to 2020. The results of the current study will provide insight into the land-use planners, government, and non-governmental organizations (NGOs) for the necessary sustainable land-use practices. © The Author(s), under exclusive licence to Springer Nature Switzerland AG 2024.Item Development of a regional-scale erosion vulnerability assessment approach along a human-intervened coast–a case study from the southern part of Kerala, India(Taylor and Francis Ltd., 2025) Parvathy, M.M.; Balu, R.; Dwarakish, G.S.The coastal district of Thiruvananthapuram, situated in the southern part of the state of Kerala, is endowed with sandy beaches, majestic cliffs, scenic backwaters and rocky promontories, aside from hosting a sizeable coastal population, well-known tourist attractions, unique biodiversity, and numerous developmental activities. However, erosion is one hazard that gravely impacts these zones, disturbing the coastal environment and affecting the lives of thousands residing in these regions. The present study attempts to identify the critical vulnerable areas to erosion, considering the combined influence of hazard parameters, i.e. drivers of erosion and risk parameters, i.e. the assets at stake. A multi-criteria decision-making approach, integrated with expert ranking, is adopted in the present study to identify and classify the vulnerable stretches, demanding urgent intervention to prevent further erosion and safeguard vital resources. The results indicate that approximately 10% of the coast falls under low vulnerability, 77% under medium vulnerability, 12 % under high vulnerability, and 1% under very high vulnerability. The coastal reaches of Shangumugham and Anchuthengu are identified as highly vulnerable and in urgent need of intervention. The spatial distribution of vulnerability necessitates a focused and site-specific management plan to tackle the present and possible erosion issues and protect critical resources. © 2025 Indian Society for Hydraulics.Item Hydrodynamic performance of floating kelp farms: Wave attenuation and coastal protection potential(Elsevier Ltd, 2025) Surakshitha; Rao, M.; Rao, S.Ecologically rich coastal zone play a crucial role in supporting both biodiversity and the economy. “Soft solutions” for coastal protection, such as vegetated breakwaters and artificial reefs, harness natural features to mitigate coastal erosion. Among these, flexible floating vegetation, such as kelp farms, presents a unique mechanism by altering flow patterns differently than bed-fixed vegetation. This study experimentally investigates the effectiveness of floating kelp farms in dissipating wave energy under monochromatic regular waves. The wave heights ranging from 0.06 m to 0.18 m and periods of 1.6 s–2.8 s is considered. The study examines the effects of two non-dimensional parameters: relative farm width (w/L, 0.1 to 2.5) and relative blade length (l/d, 0.25–1.0), representing the ratios of farm width to wavelength and blade length to water depth, respectively. Under the test conditions investigated, the highest wave dissipation coefficient (Kd ? 0.8) is observed for relative blade lengths of 0.75 and 0.5 at a water depth of 0.45 m. The optimal farm configuration occurred at a relative farm width between 0.3 and 0.4. These findings contribute to a better understanding of the role of kelp farm in wave energy dissipation and highlight its potential as a sustainable alternative for coastal protection. © 2025 Elsevier Ltd