Faculty Publications
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Item Cognitive network layer in MANETs mobility aware routing protocol(2012) Zakeerhusen, A.G.; Manjappa, M.; Guddeti, G.It is intended to add cognition to make cognitive network layer in order to design and develop Quality of Service (QoS) aware adaptive routing protocol in Mobile Adhoc Networks (MANETs). QoS-aware routing is challenging as nodes in the network are free to move, the topology will be changing dynamically. Performance of AODV will be less when nodes in the network are highly mobile. In this paper, Mobility Aware Routing Protocol (MARP) model is proposed to extract a core part in MANET that is stable in terms of mobility of the nodes. This core part is a subset of MANET mobile nodes through which transmission will be done. Here selection of paths through this extracted core can ensure more QoS in time. The MARP model not only provides a better way to discover a QoS but it considers an efficient route maintenance scheme by selecting the route which has more stability as source is having knowledge about other available paths. Since MARP is multipath routing protocol, route maintenance is easy and it robust. By simulation MARP show better performance over existing AODV-on demand routing protocol. © 2012 Springer-Verlag.Item Effect of load and interface materials on thermal contact resistance between similar and dissimilar materials(Trans Tech Publications Ltd ttp@transtec.ch, 2014) Narayana, S.R.; Narayan, P.K.The thermal contact resistance (TCR) between similar and dissimilar materials (copper, aluminium, brass and type 304 stainless steel) was assessed. Copper foil, aluminium foil, lead and Sn-9Zn lead free solder were selected as thermal interface materials (TIMs). The interfacial contact pressure was varied by application of load on materials in contact. The interfacial heat flux was estimated by solving the inverse heat conduction problem (IHCP). At higher load, the temporal variation of thermal contact resistance showed early occurrence of peak and lower values of TCR. The use of thermal interface materials reduced the contact resistance between the hot source and cold sink materials. Among the interface materials used, Sn-9Zn lead free solder showed the lowest contact resistance. This was attributed to the solid to liquid phase transformation at higher temperatures and the conformance of the interface material to surfaces in contact. Factorial experiments were carried out to determine the significance of experimental variables on TCR. The analysis showed that the effect of applied load on TCR was significant compared to other parameters. © (2014) Trans Tech Publications, Switzerland.Item Effect of Sigma (σ) phase on Mechanical and Dry sliding wear(Elsevier Ltd, 2017) Davanageri, M.; Narendranath, S.; Kadoli, R.In this paper, the wear behaviour of heat treated (oil and water quenched) super duplex stainless steel (SDSS) AISI 2507 was studied using dry sliding wear test rig. Initially as received materials was solution treated at 1050°C for duration of 2 h to achieve a balanced austenite (γ) and ferrite (δ) microstructure. The effect of different heat treatment techniques on microstructure and wear behaviour was studied by heat treating specimen at 850°C for duration of 1 h and was followed by oil and water quenching. The microstructure and crystal structure were studied through scanning electron microscope (SEM) and X-ray diffraction. The sliding wear test was employed with variation in load and speed at constant sliding distance. The results reveal that wear rate increased with increase in wear parameters. The oil quenched exhibited better wear resistance than water quenched and solution treated specimen. The worn surface morphology were analysed through SEM micrographs. © 2017 Elsevier Ltd.Item Optimization of control factors in tribological studies for as cast and 1Hr T6 treated Al25Mg2Si2Cu4Fe alloy using Taguchi methods(Elsevier Ltd, 2018) Sondur, D.G.; Mallapur, D.G.; Udupa, K.R.In this study, using the predictive model offered by Taguchi, optimization of wear parameters was carried out. Controlling factors such as sliding speed, load and T6 heat treatment (homogenizing hours) were considered. Pin on disc type friction monitor was used for determing the volumetric wear rate under constant speed for as cast and 1Hr T6 treated conditions. The L16 orthogonal array, signal to noise ratio (S/N) and regression results were used to arrive at optimal control factor values that affect the volumetric wear rate of the alloy. Combination of the dominating control factors has been predicted using Taguchi technique. Predicted combination of control factors were found to be close to the experimental observations i.e load was found to be a dominant factor for volumetric wear rate. Also 1Hr T6 treated alloy shows a higher volumetric wear resistance as compared to as cast alloy. © 2017 Elsevier Ltd.Item Pre-Engineered Building Design of Gas-Insulated Substation Housed Under Pressurized Ventilation(Springer Science and Business Media Deutschland GmbH, 2021) Roopesh, N.; Swamy, K.A.; Das, B.B.Building construction in India is carried out using conventional materials like concrete but it has limitation of span and size of components. As a result, large span areas that are essentially required for housing Electrical Extra High Voltage Gas Insulated Switchgears could not be covered by simple frames and required complex frame arrangements thereby increasing the required completion time. For design, steel has been the preferred material because of its ductile, strength, flexible, recyclability nature and low cost. With technology transfers, entrepreneurs had established steel centres where entire design to production is carried under one roof and the product is erected at site. These factories had given advantage of fabricating components either ahead or parallel to the civil works at site, thus saving time. Introducing the concept of Pre-Engineered building (PEB) into structural design resulted in design optimization and many advantages, including economy and easier fabrication when compared with the Conventional Steel building (CSB). PEB construction is widely gaining popularity over regular conventional buildings in India due to its sheer advantage in time saving. However, there is a challenge of proper and optimized design suiting to the Electrical Substation requirements such as pressurized atmospheric environment, Maintenance walkways, entry of electrical Bus ducts at various levels and locations. Any overlooking of the above may lead to overall failure of the electrical system. This would make it unique from the normal conventional PEB buildings done for Ware houses, Factories, etc. © 2021, Springer Nature Singapore Pte Ltd.Item Experimental and numerical investigation on flexural bond strength behavior of corroded NBS RC beam(SpringerOpen, 2015) Shetty, A.; Venkataramana, K.; Babu Narayan, K.S.Corrosion of reinforcing steel is the most detrimental effect endangering the structural performance. Present investigation has been taken up to study the detrimental effect of corrosion on bond behavior. Experimental and numerical investigation has been carried out for four different levels of corrosion—2.5, 5, 7.5 and 10 %. Loss in mass of reinforcement bar has been taken as the basis to fix corrosion levels. Accelerated corrosion technique has been adopted to control corrosion rate by regulating current over predetermined durations. NBS beams have been investigated for performance. Concrete grade M30 and steel Fe-415 have been used. From the experimental investigation, it has been observed that bond strength degradation of 2.6 % at slip initiation and 2.1 % at end of slip have been observed for every percentage increases in corrosion level. Numerical investigation with concrete is modeled as solid 65 element and reinforcement modeled as Link 8 elements. ANSYS has yielded 3 and 2.4 % bond strength degradation values at initiation and end of slip per percentage increase in corrosion levels. © 2015, The Author(s).Item Thermal conformance parameters for assessment of heat transfer between similar and dissimilar metal contacts(John Wiley and Sons Inc, 2024) Pathumudy, R.D.; Samuel, A.; Prabhu, K.N.A novel approach to assess the thermal conformance between two metallic materials under transient conditions was proposed in the present investigation. Thermal conformance parameters (ƞ, ϴ, tg) were defined to quantify the contact condition between a metal–metal interface. To assess the effect of load and thermophysical properties of the sink and source materials on the degree of thermal conformance, a thermal conformance assessment parameter (TCAP) was proposed. Heat flux transients at the thermal interface was estimated by using an inverse heat conduction approach for various similar and dissimilar metallic surfaces in contact such as Cu─Cu, Al─Al, Al─Cu, and Cu─Al under both load and no load conditions. Commercially available silicone grease (SG) and thermal grease (CTG) were used as thermal interface materials (TIMs). The thermal conformance parameters increased with the increase in load for all the combinations of interfaces with and without TIMs. It was observed that, except for the copper–copper combination, thermal conformance parameters showed a linear relation with the TCAP. The enhancement in the heat transfer due to the application of load and TIM was validated by determining the maximum temperature difference (∆Tmax) across the interface. The experimental study revealed that the ∆Tmax decreases with the application of load and application of TIM leading to enhanced heat transfer. For the copper–copper combination, the thermal conformance depended solely on the load applied. Due to the lower thermal resistance offered by copper source/sink materials, the interfacial resistance between them becomes a dominant factor. The effect of TIM on heat absorbed by the sink was significant for the Cu/Cu interface. © 2024 Wiley Periodicals LLC.