Faculty Publications

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    Modelling for organics and nutrients release during benthal sludge stabilisation part il - Nutrients
    (2009) Bhargava, D.S.; Shrihari, S.
    Settleable solids from untreated or partially treated domestic and industrial effluents undergoing stabilisation in stream beds contain significant amount or nutrients such as ammonia and phosphates apart from carbonaceous organic material. An experimental investigation was carried out to study the contribution of biochemical oxygen demand (BOD) and nutrients by this benthal-sludge undergoing stabillisation in steam beds. Sludge was collected from a sewage channel and placed at the bottom of an experimental reactor, and a continuous flow of clean tap water was maintained, in such a manner that the sludge was not disturbed. The first part of this work contained a discussion on degreadation of carbonaceous matter. The degradation of the nutrients, such as ammonia and phosphates being released from the sediments into the overlying waters at different flow rates of over laying waters is evaluated. It was noticed that the ammonia and phosphates released from the sediments into the overlying waters become more or less uniform after some days. The ammonia release and phosphate release were found to be affected by changes in the flowrates of overlying waters. The ammonia and phosphates remaining in the top and bottom layers of the sediments also showed similar trends. Predictive models have been presented for the variation of ammonia and phophate release into the overlying water, ammonia and phosphates remaining in the sediment layers at different times and different flow rates.
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    On numerical modelling of waves, currents and sediment movement around Gurupur-Netravathi river mouth
    (2010) Radheshyam, B.; Rao, S.; Shirlal, K.G.
    This paper presents an overview of the investigations that were carried out to understand the coastal process along Bengre and Ullal at the Gurupur-Netravathi River mouth in the west coast of India. This river inlet was facing problems of migration and siltation since several decades and therefore two rubble mound breakwaters were constructed during the year 1994 as an intervention to maintain the inlet mouth. After the construction of these river training jetties, the inlet was stabilized, but severe erosion has been taking place along the Ullal spit on the south side of southern breakwater, since 1996 and heavy accretion on the North of Northern Breakwater along Bengre spit, which is now almost stabilized. This study has been undertaken to understand the hydrodynamics along the beaches adjoining the river mouth. For the present study, various field data was collected for the post monsoon season of 2006. The hydrodynamic (HD), Parabolic mild slope (PMS) and Sediment transport (ST) modules of MIKE-21 software were used to understand the hydrodynamics of the study area. Before the model was made use, it was first validated by using field data to understand the hydrodynamics of the area. Since the field data is of limited duration, data collected from the NMPT wave buoy for an entire year was used for the model simulation. From the studies it was confirmed that current direction and sediment movement follow a similar pattern in monsoon and pre-monsoon and a different pattern during post-monsoon. It is observed that the main cause of erosion is due to direct action of waves on the adjoining beaches of the coast and the beaches in the study area are generally in dynamic equilibrium with a small amount of erosion at Ullal. © 2010 CAFET-INNOVA TECHNICAL SOCIETY. All rights reserved.
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    Heterogeneous microbial oceanographic environments: Application of GIS technology in deciphering of microenvironment scenarios off the central west coast of India
    (2011) Raghavan, B.R.; Nayak, S.R.; Shylini, S.K.; Deepthi, T.; Sadatipour, S.M.T.; Chauhan, P.; Srinivasakumar, T.; Lotliker, A.; Venkat Reddy, D.; Kumaraswami, M.; Ashwini, S.; Nisaj, M.
    In the vast oceanic microbial environment of 2468.83km 2, GIS modeling techniques involving sixty query steps, enabled the deciphering of Microenvironments as low as 1.19km 2 to 38.6 km 2 for the summer of 2004 and in case of summer 2005 where 84 query steps were involved to decipher Microenvironments of 10.55km 2 to 25.94km 2. Thirtythree sampling stations were established between Betul to Ankola off the central west coast of India accounting for a spatial coverage of 2468.83km 2. GIS query-modeling investigation was carried out using spatial layers of depth, optical parameters (k-Irradiance attenuation Coefficient, c-Beam attenuation coefficient), sediment size parameters (Sediment Mean Size and Sediment Sorting) and Benthic Foraminifera Suborders (Rotaliina, Textulariina, Miliolina, Lagenina). Foraminifera have been used as a surrogate parameter. However, any microbial parameter could proxy for foraminifers providing for the numerical deciphering of microenvironments. This is suggestive of the assimilation of GIS technology for a better appreciation of microbial oceanography. © 2011 CAFET-INNOVA TECHNICAL SOCIETY. All rights reserved.
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    Geomorphological behaviour of Sasihithlu, Mangalore coast, west coast of India
    (2011) Nagaraj, G.; Karjagi, A.; Kumar, M.; Dwarakish, G.S.
    Beach geomorphological studies have been carried out with help of conventional methods and remote sensing techniques. Conventional methods include beach profile surveys and beachwidth measurements whereas remote sensing techniques involved in utilization of satellite images, digitization and analyses. Beach profile surveys and beachwidth measurements are carried out at monthly intervals over a period of one year (September 2009 to September 2010) to understand dynamics of sediment along the coastal segment of 7km at Sasihithlu, north off Mangalore coastline. Six locations are selected based on their significant site characteristics along the coastal segment. It is observed erosion with steeper slopes during the monsoon and simultaneously deposition with flat and wider exposed slopes during the fair weather season. But the more drastic and dramatic changes are observed in the vicinity of Mulki-Pavanje rivermouth, since the rivers Mulky and Pavanje bring any kind of sediments irrespective of seasons. Because of this the profiles alter dramatically in the vicinity of rivermouth. It is estimated that the Sasihithlu beach has experienced a net loss of about 2515m 3/m, a net gain of about 3525m 3/m and hence a gain of about 1010m 3/m sediments in an annual cycle. Addition to conventional methods, remote sensing analysis is also carried out to detect the influence of rivers and their flow on rivermouth system in recent decades (1988-2009) with the help of satellite images and GIS tools. It is observed that the shifting tendency of rivermouth either south or north irrespective of seasons. However a detailed investigation on shoreline pattern showed a clear indication of shifting shoreline towards south. Therefore present study suggests to construct coastal protection structures on either side of the rivermouth, through that the damage to the property could be minimized. © 2011 CAFET-INNOVA TECHNICAL SOCIETY. All rights reserved.
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    Prediction of uniaxial compressive strength, tensile strength and porosity of sedimentary rocks using sound level produced during rotary drilling
    (2011) Rajesh Kumar, B.R.; Vardhan, H.; Govindaraj, M.
    The main purpose of the study is to develop a general prediction model and to investigate the relationships between sound level produced during drilling and physical properties such as uniaxial compressive strength, tensile strength and percentage porosity of sedimentary rocks. The results were evaluated using the multiple regression analysis taking into account the interaction effects of various predictor variables. Predictor variables selected for the multiple regression model are drill bit diameter, drill bit speed, penetration rate and equivalent sound level produced during rotary drilling (Leq). The constructed models were checked using various prediction performance indices. Consequently, it is possible to say that the constructed models can be used for practical purposes. © Springer-Verlag 2011.
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    Sedimentary environs of the intertidal areas of Massawa coast: Distribution patterns of ornamental Molluscs (Gastropods) Red Sea, Eritrea
    (2012) Prabhu, H.V.; Raghavan, B.R.; Deepthi, T.; Asmelash, M.; Fsehatsion, M.; Selemun, M.; Venkat Reddy, D.
    The distribution patterns of the four orders of Gastropods with respect of the three sites i.e Tiwalet area, Gurgussum I and Gurgussum II of the intertidal areas of Massawa coast, Red Sea have been investigated to appreciate the heterogeneity in the distribution patterns. This is determined by the sediment texture. The habitat of the Molluscs in relation to the substratum in the three sites off Massawa Coast show the nature of the substrate was hard as a result of deposition of the sediments in a shallow and rapidly drying environment. In this study, 30 different species of Gastropoda were identified. All of them are members of the sub class Prosobranchia, and distributed among four orders Neogastropoda, Mesogastropoda, Archaeogastropoda, and Pyramidellomorpha. Based on the statistical Analysis of Variance (ANOVA) carried at 5% level of significance, there was a considerable variation among the three sites in the distribution patterns of the four orders of gastropods. This difference is largely due to the differences in the shell shape and structure, and the sediment textural differences in the three sites. © 2012 CAFET-INNOVA TECHNICAL SOCIETY.
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    Prediction of Mechanical Properties of Sedimentary Type Rocks Using Rotary Drilling Parameters
    (Springer, 2020) Lakshminarayana, C.R.; Tripathi, A.K.; Pal, S.K.
    The estimation of strength properties of sedimentary rocks is most often needed during the preliminary phase of many rock engineering projects carrying out in sedimentary regions. The main drawback of determining the rock properties in a test center is the requirement of the number of superior quality rock core specimens. In this experimental investigation, the uniaxial compressive strength (UCS) and tensile strength of sedimentary rocks are estimating using well-identified drilling variables and acoustic parameters obtained during the rotary type rock drilling. The drilling variables such as thrust, torque, and vibration parameters are used to develop the mathematical models of strength properties of rock. A drill type dynamometer was used to measure the drilling variables, and the vibration parameter would measure using the NI-9234 data acquisition system. The prediction efficiency of the mathematical model is evaluating using performance indices. Results show that the used experimental method can estimate the considered responses (UCS and tensile strength) with the acceptable percentage errors of 10.52% and 11.27% respectively, and may be useful to measure the UCS and BTS of sedimentary rocks in a laboratory capacity without test core samples. © 2020, Springer Nature Switzerland AG.