Faculty Publications

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Publications by NITK Faculty

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    PFWD, DCP and CBR correlations for evaluation of lateritic subgrades
    (2009) George, V.; Rao, N.C.; Shivashankar, R.
    The evaluation of subgrade strength plays a major role in pavement design. An understanding of subgrade properties enables the selection of road materials for sub-base and base courses. In developing countries like India, apart from the use of well-established traditional pavement evaluation techniques such as the California bearing ratio (CBR) test and the dynamic cone penetrometer (DCP) test, the use of non-destructive testing devices such as the portable falling weight deflectometers (PFWDs) has gained popularity in recent years. This is mainly because of the inherent capability of PFWDs in obtaining quick estimates of the modulus of subgrade in addition to their simplicity in design and portability. Thus, there exists a need to correlate the results obtained using PFWDs with those obtained using traditional approaches such as the CBR and the DCP for the benefit of road engineers. This work focuses on exploring the correlations between these approaches for lateritic soils in Dakshina Kannada district, India.
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    An economic analysis of environmental pollution and health - a case study of Bellary-Hospet sector
    (2012) Thimmaiah, S.A.; Ravi, D.R.; Rao, Y.V.; Murthy, C.S.N.
    The Earth's natural ecosystem is the basis for our life-supporting system and provides marketable goods to human and other living organisms. The natural environment has always been exploited to fulfill human needs. The green revolution and industrial revolution has caused serious threat to sustainable development for both developed and developing countries. The degradation of air, water and land has directly affected the livelihood and human health. The environmental damage increases, as the economic activity increases, in view of the fact that the association between economy and the environment are multiple, complex and important. Mining is one such activity, which significantly results in the degradation of the environment, apart from generating huge economy to the country. Hence, the identification and quantification of socio economic impact of environmental pollution caused due to increased mining activity is necessary in the broader economic analysis. The present study is envisaged with the objective to identify and evaluate the impacts of mining activity on Social, Economical and Environmental Aspects of the area and to measure its economic burden on the affected people. The ambient air quality in the selected stations of study area reveals that, the increase in iron ore production has significantly resulted in the deterioration of air quality. High particulate matter to an extent of 310 ?g/nm3 in case of SPM concentration and 160 ?g/nm3 in case of RSPM. The health data collected from the respondents have revealed, significantly more number of respondents who are suffering from dust allergy, skin allergy in the study area, where there are mines and are working as workers in those mines, contributing for higher health cost incurred through treatment. © 2012 CAFET-INNOVA TECHNICAL SOCIETY.
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    Use of Laterite as a sustainable building material in developing countries
    (CAFET INNOVA Technical Society cafetinnova@gmail.com 1-2-18/103, Mohini Mansion, Gagan Mahal Road, Domalguda, Hyderabad 500029, 2014) Kasthurba, A.K.; Reddy, K.R.; Venkat Reddy, D.V.
    Utilisation of local materials is an important step to sustainable construction to reduce transportation cost, save embodied energy, and protect the environment. This paper advocates the use of local laterite-a soil type rich in iron and alumina formed under hot and wet tropical conditions-due to its cost effectiveness and energy efficiency than that of conventional modern materials in tropical developing countries. This paper summarizes the occurrence and characteristics of laterite and then highlights the need for developing universal database of properties and standard testing protocols to facilitate evaluation and extensive use laterite in building applications. Understanding of properties and potential challenges of using this material will benefit for the development of suitable strategies/techniques for sustainable construction. Overall, this study identifies various factors that should be considered for efficient utilization and managements of laterite in construction to meet the growing demand of new housing and infrastructural in different regions of developing tropical world. © 2014 CAFET-INNOVA TECHNICAL SOCIETY. All rights reserved.
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    Study of unique merging behavior under mixed traffic conditions
    (Elsevier Ltd, 2015) Kanagaraj, V.; Srinivasan, K.K.; Sivanandan, R.; Asaithambi, G.
    Roads in developing countries carry mixed traffic with wide variations in static and dynamic characteristics of vehicles. The traffic flow is also generally devoid of lane discipline, with vehicles occupying any available road space ahead. In such a regime of traffic flow, the phenomena of merging of vehicles at intersections of two roads is complex, warranting further study. The merging maneuvers at T-intersections under congested traffic conditions were studied microscopically through video-recording. In congested situations, the merging vehicle attempts a complex merging maneuver to enter the main traffic stream. Two unique merging processes are commonly observed in mixed traffic: group and vehicle cover merging (these are generally not observed in countries such as US). The author is using these words first time in this study. These reflect the different types of driver behavior - merging in groups, and by taking cover of another vehicle. Probabilistic models for group and vehicle cover merging are developed that capture this unique merging behavior. Comprehensive microscopic data collection and extraction were carried out to study the merging process at T-intersection under congested conditions. Merging models were then estimated using maximum likelihood method with disaggregate data that was collected for a case study T-intersection in Chennai city, India. Such models can find applications in simulation of highly congested traffic flow in a realistic manner under mixed traffic conditions. They can also give insights on devising better traffic control measures at such intersections. © 2015 Elsevier Ltd.
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    Assessment of hydropower potential in Nethravathi river basin using SWAT model
    (CAFET INNOVA Technical Society cafetinnova@gmail.com 1-2-18/103, Mohini Mansion, Gagan Mahal Road, Domalguda, Hyderabad 500029, 2015) Babar, S.; Shobhita, M.P.; Ramesh, H.
    Hydropower plants have the advantage of producing renewable and clean power, the renewable and reliable energy source that serves national environmental and energy policy objectives. Therefore, the development of hydropower plant and improvements of water management have essential in contributing to sustainable growth and energy production in developing countries like India. The present study is concerned with the development of methodology and assessment of hydropower potential in the Nethravathi River basin with the help of Remote Sensing and GIS. The drainage area covers about 3190 km2 at Bantwal gauging point, and most of the land cover of the basin is dominated by forest. The basin was divided into six sub-basins based on hydrology and topography using GIS tools. The climate over the basin is coastal humid tropical and receives an average annual rainfall of about 4000 mm. sub-basin discharges were estimated using the Soil Conservation Services (SCS) curve number method. To ensure the total discharge from six sub-basins computed from SCS curve number method, the flows were routed and simulated at the gauging location using Soil and Water Assessment Tool (SWAT). SWAT model was calibrated for monthly time steps from 1998–2001, and validated for 2002–2003. Flow-duration curves (FDC) were generated for each sub-basin to assess the dependable yield. The results have shown a good agreement between observed and the simulated flows. The available discharge at 75%, 80% and 90% of time for each sub-basin were extracted from the FDC. This result were used to calculate the hydropower potential in all the six sub-basins at Q75, Q80 and Q90, by integrating thematic layers using ArcSWAT. © 2015 CAFET-INNOVA TECHNICAL SOCIETY. All rights reserved.
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    Evaluation of combustion, performance and emissions of a diesel engine fueled with bio-fuel produced from cashew nut shell liquid
    (Taylor and Francis Ltd. michael.wagreich@univie.ac.at, 2015) Dinesha, P.; Mohanan, P.
    Presently, energy security and food security are two major problems of developing countries. The use of edible oils as an alternative fuel for internal combustion may lead to a food crisis. The non-edible plant-based alternative fuel not only results in energy security but also helps to keep the environment free from pollution. In this experimental investigation, a non-edible plant-based bio-fuel cardanol produced from cashew nut shell liquid (CNSL) is used to study the combustion, performance and emissions of a single-cylinder diesel engine. The test conditions of the engine are 200 bar injection pressure and 27.5 degree bTDC injection timing. The bio-fuel blends B10M10 (10% cardanol + 80% diesel + 10% methanol), B20M10, and B30M10 (30% cardanol + 60% diesel + 10% methanol) were tested at 25%, 50%, 75%, and full load conditions. The results were compared with baseline diesel operation. From the experimental work, it was observed that the brake thermal efficiency of B10M10 and B20M10 (20% cardanol + 70% diesel + 10% methanol) is comparatively similar to that of diesel. The lower emissions of CO, hydrocarbon, and smoke are encouraging to recognize B20M10 as an optimized fuel blend for a compression ignition engine at 200 bar injection pressure and 27.5 degree bTDC. The significant factors of cardanol bio-fuel include its low cost, non-edible, abundance, and it is a by-product of the cashew nut industries. © © 2015 Taylor & Francis.
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    Trajectory data and flow characteristics of mixed traffic
    (National Research Council, 2015) Kanagaraj, V.; Asaithambi, G.; Toledo, T.; Lee, T.-C.
    Models of driving behavior (e.g., car following and lane changing) describe the longitudinal and lateral movements of vehicles in the traffic stream. Calibration and validation of these models require detailed vehicle trajectory data. Trajectory data about traffic in cities in the developing world are not publicly available. These cities are characterized by a heterogeneous mix of vehicle types and by a lack of lane discipline. This paper reports on an effort to create a data set of vehicle trajectory data in mixed traffic and on the first results of analysis of these data. The data were collected through video photography in an urban midblock road section in Chennai, India. The trajectory data were extracted from the video sequences with specialized software, and the locally weighted regression method was used to process the data to reduce measurement errors and obtain continuous position, speed, and acceleration functions. The collected data were freely available at http://toledo .net.technion.ac.il/downloads. The traffic flow characteristics of these trajectories, such as speed, acceleration and deceleration, and longitudinal spacing, were investigated. The results show statistically significant differences between the various vehicle types in travel speeds, accelerations, distance keeping, and selection of lateral positions on the roadway. The results further indicate that vehicles, particularly motorcycles, move substantially in the lateral direction and that in a substantial fraction of the observations, drivers are not strictly following their leaders. The results suggest directions for development of a driving behavior model for mixed traffic streams. © © 2015 National Academy of Sciences. All rights reserved.
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    Evaluation of right-turn lanes at signalized intersection in non-lane-based heterogeneous traffic using microscopic simulation model
    (Maney Publishing michael.wagreich@univie.ac.at, 2015) Asaithambi, G.; Sivanandan, R.
    In developing countries like India, the traffic on urban roads is highly heterogeneous in nature, with vehicles of widely varying static and dynamic characteristics. This type of traffic is characterized by lack of queue and lane discipline (lane-less movement) based on availability of spaces near intersections. Moreover, at intersections, straight-through, left-, and right-turning vehicles seek to occupy the same physical space. In such situations, the through vehicles are susceptible to delays in the absence of turn lanes for the left-turning and right-turning vehicles and vice versa. Models suitable for analysis of such traffic flow hardly exist, and most of the available models are limited in scope. In the current study, a microscopic traffic simulation model for signalized intersection is developed specifically for heterogeneous traffic. This model covers different vehicle types and allows for some special behavior, such as seepage of two-wheelers to fronts of queues. Detailed study of queue formation and dissipation were done microscopically under non-lane-based traffic conditions near intersection area. The model was calibrated and tested with data from Chennai city, India, and its predictions were found to be in close agreement with the field data. In addition, the model makes a significant contribution to the study of right-turn lane (RTL) on delays to vehicles. In general, RTL is found to be advantageous for most cases of approach volumes and right-turn proportions. The optimal lengths of RTL are suggested for various approach volumes and right-turn proportions. © 2015 W. S. Maney & Son Ltd.
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    Modeling free-flow speeds on undivided roads in mixed traffic withweak lane discipline
    (SAGE Publications Ltd, 2018) Chathoth, V.; Asaithambi, G.
    In developing countries like India, transportation systems are characterized by limited roadway infrastructure and lack of operation and management experience. Hence, there exists a need to evaluate a performance indicator that reflects the current level of service (LOS) of a road facility. Free-flow speed (FFS) is a key parameter used to express LOS assessment. The objective of this study is to develop FFS prediction models for undivided roads with mixed traffic conditions in both urban and rural settings in India. Traffic data were collected from two-way two-lane undivided roads in southern India during freeflow traffic conditions using videographic method. Various class-specific and site-specific characteristics, such as vehicle class, subclass, carriageway width, link length, number of side roads, lateral clearance, land use type, and area type, were investigated and their influence on FFS evaluated. Statistical tests assessed the variations of obtained FFS with different vehiclespecific and site-specific factors. Free-flow prediction models were developed using linear regression method. The developed models show that FFS increases with greater carriageway width, lateral clearance, and link length, and decreases with increase in number of side roads. In general, FFS is higher in rural areas than urban areas. Similarly, open areas have higher FFS than residential, institutional, and commercial areas. The model can be used to predict FFS of undivided roads if site-specific and vehicle-specific data are known. This study finds interesting applications in capacity and LOS analysis, accident analysis, and before-and-after studies of road improvement schemes. © National Academy of Sciences: Transportation Research Board 2018.
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    Modeling duration of lateral shifts in mixed traffic conditions
    (American Society of Civil Engineers (ASCE) onlinejls@asce.org, 2018) Asaithambi, G.; Joseph, J.
    Traffic on urban roads in developing countries is characterized by wide mix of vehicles with loose lane discipline, which results in parallel movement of vehicles in the same lane. Hence, vehicles not only interact longitudinally with the vehicles ahead but also laterally with vehicles to the sides. Lateral movements have a significant impact on the characteristics of traffic flow and therefore are of great importance in microscopic traffic simulation models. Existing simulation models for mixed traffic conditions model lateral shifts (lateral movements) as an instantaneous process but neglects detailed modeling. However, the duration for lateral shifts is generally in the range of 0.5-15 s. The omission of lateral shift duration from simulation models may have a significant impact on simulation outputs. Also, different vehicle types may have different lateral shift durations due to variations in their physical and operational characteristics. This paper attempts to develop a vehicle-specific lateral shift duration model by considering different explanatory variables such as direction of lateral shift, available space gaps, speeds of subject vehicle and surrounding vehicles, vehicle types, and clearance. The models were estimated using trajectory data collected during medium-flow conditions from an urban arterial in Chennai city, India. The findings from this study have direct implications on modeling lateral shifts in microscopic traffic simulations to be developed specifically for mixed traffic conditions. © 2018 American Society of Civil Engineers.