1. Journal Articles
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Item Aqueous corrosion behaviour of ductile iron and ductile iron containing 1 wt. pct. chromium(1997) Surendranathan A.O.; Hebbar, K.R.; Sudhaker Nayak, H.V.Ductile irons with graphite in spheroidal form enjoy the processing characteristics of grey iron and mechanical properties of steel. This paper describes the corrosion behaviour of ductile iron containing 1 wt. % chromium in sea water, dilute sulphuric acid and dilute sodium hydroxide solutions and compares with that of unalloyed ductile iron. Study is made in as-cast, annealed and cold worked (upto 28% reduction in thickness) conditions at three different temperatures. Since the alloying addition brings changes in the proportion of phases, the corrosion behaviour of the two materials studied were different, though alloying addition is small, indicating corrosion behaviour to be structure sensitive.Item Unsteady 2-D flow field characteristics for perforated plates with a splitter(2004) Yaragal, S.C.Wind tunnel experiments were conducted under highly turbulent and disturbed flow conditions over a solid/perforated plate with a long splitter plate in its plane of symmetry. The effect of varied level of perforation of the normal plate on fluctuating velocities and fluctuating pressures measured across and along the separation bubble was studied. The different perforation levels of the normal plate; that is 0%, 10%, 20%, 30%, 40% and 50% are studied. The Reynolds number based on step height was varied from 4�103 to 1.2�104. The shape and size of the bubble vary with different perforation level of the normal plate that is to say the bubble is reduced both in height and length up to 30% perforation level. For higher perforation of the normal plate, bubble is completely swept out. The peak turbulence value occurs around 0.7 to 0.8 times the reattachment length. The turbulence intensity values are highest for the case of solid normal plate (bleed air is absent) and are lowest for the case of 50% perforation of. the normal plate (bleed air is maximum in the present study). From the analysis of data it is observed that ?u?2/(?u?2), (the ratio of RMS velocity fluctuation to maximum RMS velocity fluctuation), is uniquely related with dimensionless distance y/Y?, (the ratio of distance normal to splitter plate to the distance where RMS velocity fluctuation is half its maximum value) for all the perforated normal plates. It is interesting to note that for 50% perforation of the normal plate, the RMS pressure fluctuation in the flow field gets reduced to around 60% as compared to that for solid normal plate. Analysis of the results show that the ratio [C?p max /-Cpb(1 - ?n)], where C?p max is the maximum coefficient of fluctuating pressure, Cpb is the coefficient of base pressure and ?n is the perforation level (ratio of open to total area), for surface RMS pressure fluctuation levels seems to be constant and has value of about 0.22. Similar analysis show that the ratio [C?p max /-Cpb(1 - ?n)] for flow field RMS pressure fluctuation levels seems to be constant and has a value of about 0.32.Item �ber den Einflu� von Schwefelwasserstoff auf die Korrosion des Eisens in sauren L�sungen(1979) Ramchandran, T.; Bohnenkamp, K.An Eisenelektroden wurden in anges�uerten Perchlorat und Sulfatl�sungen nach Einleiten von Schwefelwasserstoff erheblich ver�nderte Stromdichte?Potentialkurven beobachtet. Gegen�ber den reinen L�sungen ergeben sich mit Schwefelwasserstoff stark erh�hte anodische Stromdichten und bis um den Faktor 10 erh�hte Korrosionsgeschwindigkeiten. Dabei sind die anodischen Tafelgeraden log iA = f (E) mit H2S nur rund halb so steil wie ohne H2S. Wahrscheinlich wirken die SH??Ionen �hnlich wie die OH??Ionen als Katalysator der Eisenaufl�sung, sind aber bis fast zur S�ttigung absorbiert. Copyright � 1979 Verlag GmbH & Co. KGaA, WeinheimItem Trifluoromethyl-quinolin-yl-thio-propanohydrazide as an effective inhibitor of mild steel corrosion in HCl solution(2006) Ramesh, Saliyan, V.; Adhikari, A.V.3-{[8-(trifluoromethyl)quinolin-4-yl]thio}propanohydrazide(TFQTPH) was synthesized, characterized and tested as a corrosion inhibitor for mild steel in 1 M HCl and 2 M HCl solution using different techniques: potentiodynamic polarization and electrochemical impedance spectroscopy (EIS). The results showed that TFQTPH is an excellent inhibitor for mild steel in acid medium. The inhibition was assumed to occur via adsorption of the inhibitor molecule on the metal surface. In the temperature range 20� to 60� C, the TFQTPH adsorption follows Langmuir isotherm model. The protection efficiency increased with increasing inhibitor concentration (10 to 500 ppm), even at higher temperature also, it recorded good inhibition efficiency. � 2006 SAEST.Item Tropical river basin development- a case study in selection of sites for vented dams(2008) Rajeev, V.S.; Mahesha, A.Scarcity of water in various parts of the country is of major concern in the recent years. Even places with very high annual rainfall face the water shortage during the non-monsoon months. This indicates scope for the improvement in planning, development and management of water resources. Dakshina Kannada, a coastal district of Karnataka, on an average receives more than 3000 mm of annual rainfall and still faces acute shortage of drinking water during the summer months. The river Netravathi which is a tropical, seasonal river of the district is the major source of water for the region including rapidly progressing Mangalore city with a population of more than 5 lakhs. Due to the hydro-geological characteristics of the area, construction of major dams across the rivers is not feasible. Under these circumstances, construction of small structures such as vented dams may be appropriate in conserving the river water. To achieve the required storage and to conserve the river water, a series of such dams is proposed. The average annual yield of the river is about 11,502 Mm3. At present, the amount of utilized is less than 1% and there is large scope for conserving river water. This paper highlights the site selection criterion for the construction of such vented dams across the river Netravathi. These dams when constructed will allow optimal river basin development without causing inundation. The total capacity of the dams is about 101.91 Mm3 with further scope to increase the height of the dams by providing proper bank protection works. The vented dam at the downstream end of the river nearest to the sea also serves the purpose of salt water exclusion, protecting the adjoining aquifers from salt water intrusion during the summer months. � 2008 Taylor & Francis Group, LLC.Item Treatment of domestic wastewater by association of up flow anaerobic and aerobic biofilters(2007) Srinikethan, G.; Shrihari, S.; Pradeepan, V.S.Laboratory studies were conducted to assess the performance of association of up flow anaerobic & aerobic biofilters in treating domestic wastewater. Two simple models of 8 litres capacity, one up flow anaerobic biofilter (AnBF) packed with support media granite of size 20 mm and another up flow aerobic biofilter(ABF) packed with support media granite of size 10 mm respectively were installed. The experimental anaerobic & aerobic biofilters were made of PVC tubes. The hydraulic retention time (HRT) was maintained as 12 hours in anaerobic biofilter and 8 hours in aerobic biofilter. The study was carried out for a period of 90 days. The association of up flow anaerobic & aerobic biofilters demonstrated the average Turbidity, Suspended Solids, BOD and COD removal 96.56%, 96.53%, 95.67% and 90.42% respectively. The waste treatment performance indicates that the association of up flow anaerobic & aerobic biofilters is a promising technique for (sub) tropical countries. Copyright � Enviromedia.Item Treatment of domestic wastewater in up flow anaerobic biofilters (using granite as packing material)(2005) Srinikethan, G.; Shrihari, S.; Pradeepan, V.S.Laboratory studies were conducted to assess the influence of media related factors such as porosity and pore size and specific surface area on performance of up flow anaerobic biofilters (ABFs). Two simple model of 8 litres capacity up flow anaerobic biofilters (ABFs), one packed with support media granite of size 50 to 40 mm and the other packed with granite of size 25 to 20 mm were installed. The experimental anaerobic biofilters were made of PVC tubes. The hydraulic retention time (HRT) was maintained as 12 hours. The study was carried out for a period of 90 days. The waste treatment performance indicates that the biofilter associated with media of the lesser pore size and porosity with higher specific surface area demonstrated the highest BOD and COD removal 91.03% and 82.50% respectively. Copyright � Enviromedia.Item Treatment of domestic wastewater by UASB system for tropical countries(2004) Srinikethan, G.; Shrihari; Pradeepan, V.S.The present study deals with the treatment of weak domestic wastewater in UASB(up flow anaerobic sludge blanket) reactor system. An experimental reactor, made of PVC tubes, 24 litre capacity was used for the experiment to evaluate the performance of the reactor. The HRT(hydraulic retention time) was maintained as 3 days. The study was carried out for a period of 40 days. The results of the experiment indicate that the anaerobic treatment of domestic wastewater in UASB reactor is a promising technique for tropical countries. � Enviromedia.Item Transportation of granite statues(1989) Basavarajaiah, B.S.This paper deals with the problems faced during the transportation of two large granite monolith statues weighing 180 t and 120 t respectively through the narrow and winding country-roads on the western plains of the state of Karnataka. A brief resume of the problems faced during this operation and how these were overcome successfully have been presented.Item Z-scan and degenerate four wave mixing studies on newly synthesized copolymers containing alternating substituted thiophene and 1,3,4-oxadiazole units(2006) Kiran, A.J.; Udayakumar, D.; Chandrasekharan, K.; Adhikari, A.V.; Shashikala, H.D.The third-order nonlinear optical properties of newly synthesized copolymers containing alternating substituted thiophene and 1,3,4-oxadiazole units have been studied in DMF solution at 532 nm by using single beam Z-scan and degenerate four wave mixing techniques with nanosecond laser pulses. The variation of nonlinear response among the copolymers clearly indicates the dependence of ?(3) on donor and acceptor type of units present in the copolymers. The nonlinear refractive index, n2, of the investigated copolymers is found to be negative and the magnitude is as high as 10-10 esu. All samples exhibit strong reverse saturation absorption at the wavelength used and show good optical limiting of nanosecond pulses. The concentration dependence of n2 and the two-photon absorption coefficient (?) has been studied. � 2006 IOP Publishing Ltd.