Indonesian Institute of Sciences

About: Indonesian Institute of Sciences is a facility organization based out in Jakarta, Indonesia. It is known for research contribution in the topics: Population & Genus. The organization has 4795 authors who have published 10544 publications receiving 76990 citations. The organization is also known as: Indonesian Institute of Sciences Cibinong, Indonesia.

Superparamagnetic Behaviour and Surface Analysis of Fe3O4/PPY/CNT Nanocomposites

Abstract: The superparamagnetic property of nanomaterials such as Fe3O4 has been considered to be promising for various applications. In this paper, Fe3O4/PPY/CNT nanocomposites were synthesized with utilizing natural iron sand by a coprecipitation method. The as-precipitated Fe3O4 NPs were combined with carbon nanotubes (CNTs) using conductive polypyrrole (PPY) as linking agents. The Fe3O4/PPY/CNT nanocomposites were systematically characterized by FE-SEM, EDS, XRD, BET, and FTIR. Furthermore, the effects of CNTs on magnetic and thermal properties of nanocomposites were investigated by VSM and thermal gravimetric analysis (TGA), respectively. The composites exhibited significant decrease of coercivity value with the content of CNTs increasing. The VSM result confirmed that Fe3O4/PPY/CNT nanocomposites were superparamagnetic. It was found that by increasing the amounts of CNTs, the magnetization of Fe3O4/PPY/CNT nanocomposites gradually decreased. The addition of CNTs is intended to improve the mesoporous property as proved by BET analysis which has the potential application as a nanocatalyst.

Interannual Variability of the Sulawesi Sea Circulation Forced by Indo‐Pacific Planetary Waves

Abstract: The regional INDESO model configured in the Indonesian seas from 2008 to 2016 is used to study the mechanisms responsible for the variability of the currents in the Sulawesi Sea of the Indonesian seas. The model simulation compares reasonably with the seasonal to interannual variability of the moored current meter observations in the upper 350m or so of the Maluku Channel during 2015 and 2016. The interannual variability of the currents in the eastern Sulawesi Sea in the model is found to be associated with both the Pacific and Indian Ocean remote forcing. Lag correlation analysis and a theoretical linear wave model simulation suggest that both the equatorial Kelvin waves from the Indian Ocean and the coastally trapped Kelvin waves from the western Pacific along the Philippine coast can propagate through the Indonesian seas and arrive at the Maluku Channel. In particular, from mid-2015 to 2016 the Indian Ocean Kelvin waves are found to significantly impact the sea level anomaly variability in the Maluku Channel. The results indicate the importance of Indo-Pacific planetary waves to the interannual variability of the currents in the Sulawesi Sea at the entrance of the Indonesian seas. Plain Language Summary The Indonesian seas provide a tropical connection for the climate systems over the tropical Pacific and Indian Oceans, the dynamics of which are not clear so far. This study uses a high-resolution computer model to simulate the currents measured by an acoustic current meter attached to a deep ocean mooring in the Maluku Channel of the northeastern Indonesian seas. Based on the successful simulation, the dynamics of the interannual variations of the circulation in the Maluku Channel are studied using the model and a simplified theoretical linear model. The interannual currents and sea level variability in the Maluku Channel are found to be affected by both the Indian Ocean Kelvin waves and the Philippine coastal Kelvin waves. It is found that the Indian Ocean Kelvin waves dominate the sea level variability in the Maluku Channel from mid-2015 to 2016. In early 2015, the sea level variability in the Maluku Channel is dominated by the coastal Kelvin waves from the east Philippine coasts. The results are important for the understanding of the circulation at the entrance of the Indonesian seas and of the Indo-Pacific interactions through the propagation of the planetary waves.

Improvement of BCI Performance Through Nonlinear Independent Component Analysis Extraction

Abstract: Electroencephalogram (EEG) recordings provide an important means of brain-computer communication, but their classification accuracy and transfer rate are limited by unexpected signal variations due to artifacts and noises. In this paper, a nonlinear independent component analysis (NICA) extraction method for brain signal based EEG-P300 are proposed. The performance of the proposed method is investigated through a comparison of well known extraction methods (i.e., AAR, JADE, and SOBI algorithms). Finally, the promising results reported here reflect the considerable potential of EEG for the continuous classification of mental states.

An examination of species within the genus surirella from the malili lakes, sulawesi island, indonesia, with descriptions of 11 new taxa

Abstract: With 35 taxa reported by Hustedt (1942a), the genus Surirella (Turpin) is one of the most taxonomically rich and important genera in the Malili Lakes, a system of five ancient lakes located on the island of Sulawesi, Indonesia. We examine in detail the taxonomy of diatoms within the genus Surirella from the Malili Lakes. We also statistically evaluate valve morphology and relationships among taxa, and describe 11 new taxa. Results show Surirella taxa clustered according to unique combinations of morphological characteristics. Individuals within clusters often shared common valve shape, torsion, and presence of siliceous features including spines, spinules, and novel structures such as siliceous tendrils and tubular processes along the median area. We demonstrate that the siliceous tendrils of Surirella sublinearis and its varieties, and S. tenacis are used for attachment to substrata and further postulate that the evolutionary development of attachment features contributes to the substantial diversity of ...