Faculty Publications

Now showing 1 - 2 of 2

Analysis of cortical rhythms in intracranial EEG by temporal difference operators during epileptic seizures
(Elsevier Ltd, 2016) Malali, A.; Chaitanya, G.; Gowda, S.; Majumdar, K.
Brain oscillations have traditionally been studied by time-frequency analysis of the electrophysiological signals. In this work we demonstrated the usefulness of two nonlinear combinations of differential operators on intracranial EEG (iEEG) recordings to study abnormal oscillations in human brain during intractable focal epileptic seizures. Each one dimensional time domain signal was visualized as the trajectory of a particle moving in a force field with one degree of freedom. Modeling of the temporal difference operators to be applied on the signals was inspired by the principles of classical Newtonian mechanics. Efficiency of one of the nonlinear combinations of the operators in distinguishing the seizure part from the background signal and the artifacts was established, particularly when the seizure duration was long. The resultant automatic detection algorithm is linear time executable and detects a seizure with an average delay of 5.02 s after the electrographic onset, with a mean 0.05/h false positive rate and 94% detection accuracy. The area under the ROC curve was 0.959. Another nonlinear combination of differential operators detects spikes (peaks) and inverted spikes (troughs) in a signal irrespective of their shape and size. It was shown that in a majority of the cases simultaneous occurrence of all the spikes and inverted spikes across the focal channels was more after the seizure offset than during the seizure, where the duration after the offset was taken equal to the duration of the seizure. It has been explained in terms of GABAergic inhibition of seizure termination. © 2016 Elsevier Ltd. All rights reserved.
Exploring the Potential of Copper Slag and Quartz as Fine Aggregate Replacements in Concrete: A Comprehensive Study
(Multidisciplinary Digital Publishing Institute (MDPI), 2023) Yadav, A.; Jayappa, S.M.; Mahadevaiah, R.R.; Gowda, S.; Jitesh, N.; Pasmanabh, J.; Anand, V.; Muralidhar, M.
In the realm of civil construction, river sand is an essential ingredient that cannot be overlooked. With the ever-increasing surge in construction activities, the demand for river sand has surged in tandem, resulting in its escalating scarcity, and subsequently, its price surge across the entire nation. This study delves into the utilization of copper slag as a viable alternative in the production of cement mortars, particularly as a partial replacement for fine aggregates. Experiments were conducted on concrete cubes and cylinders to determine the compressive strength and split tensile strength, respectively. Five cubes and cylinders were tested after 7, 14, and 21 days of curing. The extensive characterization of copper slag was conducted, encompassing its chemical composition, mineralogical attributes, and size distribution. The findings highlight that mortars containing copper slag exhibit superior compression resistance compared to the river sand-based mortars. Specifically, the 50% replacement of river sand with a blend of copper slag and quartz demonstrates the highest strength, surpassing the other compositions. Notably, the partial substitution of sand with copper slag outperforms both quartz and sand individually, with the optimal strength achieved at a 50% replacement rate. Copper slag, with its pozzolanic properties, showed a greater strength-enhancing potential, while quartz also exhibited positive effects. These findings are promising for optimizing concrete mix designs, reducing the environmental impacts caused by industrial by-products, and exploring natural alternatives. © 2024 by the authors. Licensee MDPI, Basel, Switzerland.

Faculty Publications

Browse

Filters

Settings

Sort By

Results per page

Search Results