Journal Articles
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Item Challenges in Design, Data Placement, Migration and Power-Performance Trade-offs in DRAM-NVM-based Hybrid Memory Systems(Taylor and Francis Ltd., 2023) Rai, S.; Talawar, B.DRAM-NVM-based hybrid memory opens up a varied range of power-performance-area operational configurations through page migration between the high-performance DRAM and the reliable NVM. The amalgamation of two technologies requires various modifications for the existing monolithic DRAM-based systems. This paper summarizes the current research work in the areas of data placement and page migration in hybrid memories. The challenges and design solutions from a range of NVMs-PCM, STT-RAM, ReRAM is presented. This paper also identifies several research challenges in these areas. © 2023 IETE.Item A comprehensive review on evaporative cooling systems(Elsevier B.V., 2023) Kapilan, N.; Isloor, A.M.; Karinka, S.The evaporative cooling system (ECS) is one of the cheapest and oldest cooling technologies. The conventional single stage ECS is most widely used in domestic application, particularly in hot and dry regions. However, in this system, the temperature of the air cannot be reduced below the wet bulb temperature of the air. The multistage ECS system helps to overcome this problem. The combination of direct and indirect ECS helps to reduce the temperature of the air below its wet bulb temperature. The further reduction in air temperature may be achieved with the help of the cooling coil driven by vapour compression system. The energy consumed by the ECS is lower as compared to vapour compression refrigeration system. The ECS can be driven with the help of solar power. The conventional cooling pad used in ECS can be replaced with locally available natural fibers to reduce initial cost and to reduce dependence on import of cooling pads. The performance of the ECS can be improved with the help of heat pipe. Various techniques are used to enhance ECS's performance. The performance of the vapour compression refrigeration system can be improved with the help of ECS. This paper discusses basics and types of ECS, methods used to increase the performance of ECS, types of natural fiber cooling pad material, process variables affecting ECS, recent technical advancements, challenges and opportunities. © 2023 The AuthorsItem A laboratory investigation on single row suspended porous pipes was conducted in a two-dimensional regular wave flume to study their hydraulic performance. The effects of porosity, water depth, incident wave steepness and relative wave height on transmission and reflection coefficients were studied. It was found that (a) as incident wave steepness increases transmission coefficient Kt decreases and reflection coefficient Kt increases; (b) water depth has insignificant effect on Kt and Kt for porous pipes; (c) as porosity decreases Kt decreases and Kt increases; and (d) the range of variables studied, as the relative wave height increases Kt increases and Kr decreases.(Performance of single row of suspended porous pipe breakwater) Rao, S.; Rao, N.B.S.; Reddy, Y.V.B.2001Item Long haul, repeaterless, coherent optical multichannel communication systems employing hybrid multiplexing schemes wherein Wavelength Division Multiplexing (WDM) and Optical Code Division Multiplexing (OCDM) are combined is analyzed in the presence of performance limiting factors such as Inter Channel Interference (ICI), Stimulated Raman Scattering (SRS) and detector shot noise. Error control coding techniques in the form of rate 1/2 convolutional codes are employed in the system to counter these performance limiting factors. It is seen that the use of error control coding technique can enhance the system performance to such an extent that a Bit Error Rate (BER) performance of less than 10-8 is achievable without crossing the SRS power threshold for as many as 1000 to 1200 channels. Advantages of the hybrid multiplexed system over systems relying solely on WDM or OCDM are also discussed along with the advantages of using error control coding compared to optical amplification in countering the performance degrading factors.(Fachverlag Schiele und Sohn GmbH, Coding to enhance performance of hybrid multiplexed coherent optical communication systems in the presence of ICI and SRS) Kumar, M.S.; Bhat, K.N.H.; Umesh, G.2003Item A multichannel reservation-based channel-access protocol is investigated in this paper. The available system bandwidth is divided into distinct frequency channels. Under the protocol, one channel (the control channel) is used to exchange reservation messages and the remaining channels (the traffic channels) are used for information-bearing traffic. The performance of this scheme is compared to that of a single-channel reservation-based protocol. A simple contention-based slotted-Aloha protocol is also considered. Performance results take into account the effects of multiple-access interference on acquisition and packet errors. Results show that the reservation-based approach is advantageous under conditions of high traffic. In addition, a pacing mechanism that mitigates multiple-access interference and promotes fairness is described, and results are presented that demonstrate its effectiveness.(Baltzer Sci Publ, Unslotted multichannel channel-access protocol for distributed direct-sequence networks) Raghavan, A.R.; Baum, C.W.2004Item 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 Influence of diethyl ether on the performance and emissions of a compression ignition engine fuelled with biodiesel(Penerbit Akademia Baru, 2020) Kapilan, N.; Prabhu S, S.; Vasudeva, M.India is one of the major importers of petroleum products and hence government of India has taken several steps to find suitable alternative fuels to the fossil fuels. The biodiesel derived from non-edible oils is considered as an immediate substitute for the fossil diesel. In this work, biodiesel was produced from non-edible honge oil and used as substitute for the diesel. The engine tests were carried out on a diesel engine which is most widely used for agricultural purpose. From the engine tests, we observed that the diesel engine performance with biodiesel is lower than the diesel due to lower volatility and slightly higher viscosity of the biodiesel. Hence, the objective of this work is to study the impact of diethyl ether (DEE) on the performance of the engine. The engine tests were conducted on a single cylinder, water cooled, compression ignition engine at steady state condition. The engine test results showed an increase in brake thermal efficiency and reduction in engine exhaust emissions such as CO, HC and smoke with the addition of DEE as an additive. From this work we conclude that the DEE can be used as an ignition improver for the honge oil biodiesel. © 2020 PENERBIT AKADEMIA BARU - All rights reserved.Item Stone-Wales Defect Induced Performance Improvement of BC3 Monolayer for High Capacity Lithium-Ion Rechargeable Battery Anode Applications(American Chemical Society, 2020) Thomas, S.; Madam, A.K.; Asle Zaeem, M.A.First-principles density functional theory (DFT) computations were adopted to assess the potential application of a boron carbide (BC3) monolayer with point and topological defects as an anode material in alkali metal-based lithium (Li) ion rechargeable batteries. Results show that point defects (mono and bi vacancies) induce a large structural deformation upon Li intercalation which restricts their use for anode application. However, the Stone-Wales defect filled BC3 monolayer shows high structural stability with a negative Li binding energy of -1.961 eV in comparison with -0.930 eV of its pristine form. It is also noticed that after adsorbing the Li atom, the semiconducting characteristics of both the pristine and Stone-Wales defect filled BC3 monolayers are transformed into metallic, electrically conductive states. More importantly, the Li alkali metal atom shows fast diffusion on the surfaces of both the pristine and the Stone-Wales defect filled BC3 monolayers with low energy barriers of 0.34 and 0.33 eV, respectively. Besides, both the pristine and Stone-Wales defect filled BC3 monolayers exhibit high theoretical specific capacities of 1144 and 1287 mAhg-1, which are much higher than that of a traditional graphite anode and stand among the highest values of anode materials detailed in literature. The Li alkali metal intercalated monolayers BC3 show small average open-circuit voltages of 0.485 and 0.465 V for pristine and Stone-Wales defect cases, respectively. On the basis of the aforementioned details, the present study suggests that the Stone-Wales type topological defect incorporated BC3 monolayer is a promising anode material for Li-ion based rechargeable batteries with high storage capacity, low Li diffusion energy barrier, and low average open-circuit voltage. © 2020 American Chemical Society.Item Application ANN Tool for Validation of LHD Machine Performance Characteristics(Springer, 2020) Balaraju, B.; Raj, G.R.; Murthy, C.S.Survival of industries has become more critical in the present global competitive business environment unless they produce their projected production levels. The accomplishment of this can be possible only by maintaining the men and machinery in an efficient and effective manner. Hence, it is more essential to estimate the performance of utilized equipment for reaching/achieving future goals. The present study focuses on the estimation of underground mining machinery such as the load–haul–dump machine performance characteristics using ‘Isograph Reliability Workbench 13.0’ software. The allocation of best-fit/goodness-of-fit distribution was made by utilizing the Kolmogorov–Smirnov test (K–S) test. The parameters were recorded based on the best-fitted results using the maximum likelihood estimate test. Further, a feed-forward-back-propagation artificial neural network (ANN) tool has been used to develop the models of reliability, availability and preventive maintenance time intervals. The number of neurons was selected with the Levenberg–Marquardt learning algorithm in the hidden layer as the optimal value. The output responses were predicted corresponding to the optimal values. Further, an attempt has been made to validate the computed results with ANN predicted responses. The recommendations are suggested to the industry based on the results for the improvement of system performance. © 2020, The Institution of Engineers (India).Item Optimum location and influence of tilt angle on performance of solar PV panels(Springer Science and Business Media B.V., 2020) Khan, T.M.; Soudagar, M.E.M.; Kanchan, M.; Afzal, A.; Banapurmath Nagaraj, N.R.; Akram, N.; Mane, S.D.; Shahapurkar, K.With the growing demand of economically feasible, clean, and renewable energy, the use of solar photovoltaic (PV) systems is increasing. The PV panel performance to generate electrical energy depends on many factors among which tilt angle is also a crucial one. Among hundreds of research work performed pertinent to solar PV panels performance, this work critically reviews the role of tilt angles and particularly locating the optimum tilt angle using different methods. The past data collected for analysis can be categorized mainly into mathematical model based, experimental based, simulation based, or combination of any of these. Single-axis tracking, dual-axis tracking, simple glass cover, hydrophobic glass cover, soiled glass, clean glass, partial shadow, use of phase-change material, computational fluid dynamic analysis, etc., are the novel methods found in the literature for analysis and locating the optimum tilt angle. For illustration purpose, few figures are provided in which the optimum tilt angle obtained on monthly, seasonally, and annual basis is shown. Research works are growing in the field of computations and simulations using online software and codes. Pure mathematical-based calculations are also reported but the trend is to combine this method with the simulation method. As the PV panel performance is found to be affected by number of parameters, their consideration in any single study is not reported. In future, work is required to carry out the experiment or simulation considering the effect of soiling, glass material, temperature, and surrounding ambience on the location of optimum tilt angle. As a whole, the optimum tilt angles reported for locations exactly on the equator line, i.e., 0° latitude, ranges between ? 2.5° and 2.5°, for locations just above the equator line, i.e., latitude 2.6°–30° N ranges between 5° and 28°, for 40°–70° N, it is 29°–40°, and for 71°–90° N, it is 41°–45°. For locations at 2.6°–30° S, optimum tilt angles range between ? 4° and ? 32°, 30°–46° S, it is ? 33° to ? 36°, 47°–65° S, it is ? 34° to ? 50°, and for 66°–90° S it is ? 51° to ? 62°. © 2019, Akadémiai Kiadó, Budapest, Hungary.