Indian Institute of Technology Indore

About: Indian Institute of Technology Indore is a education organization based out in Indore, Madhya Pradesh, India. It is known for research contribution in the topics: Fading & Support vector machine. The organization has 1606 authors who have published 4803 publications receiving 66500 citations.

Effect of Curing on Micro-Physical Performance of Polypropylene Fiber Reinforced and Silica Fume stabilized Expansive Soil Under Freezing Thawing Cycles.

Abstract: This study presents the micro-physical investigation of polypropylene (PP) fiber-reinforced, and silica fume (SF) stabilized expansive soil (BC) subgrade. The coupling effect of soil, PP fiber, and SF has been evaluated under the freezing-thawing (F-T) cycle to assess the durability of treated BC Soil. The curing method and duration staggeringly influence the strength of SF treated BC soil; therefore, three different curing method, i.e., moisture-controlled curing (MC), gunny bag curing (GC), and water submerged curing (SC) to a period of 7, 14, and 28 days were considered. The BC soil has been reinforced with 0.25%, 0.50%, and 1.00% PP fiber and stabilized with 2%, 4%, 6% and 8% SF. The physical, chemical, and microstructural properties were determined before and after 2,4,6,8,10 F-T cycles. With the increase in SF content, the unconfined compressive strength of the expansive soil has been increased due to the formation of Calcium Silicate Hydrate (C-S-H) gel. The chemically inert, hydrophobic, non-corrosive nature, and higher tensile strength of PP fiber, it has a higher potential to reinforce the BC soil for durability under tensile failure. This research confirms the possibility of incorporating SF and PP Fiber in road work applications, with significant environmental benefits.

AIE active fluorescent organic nanoaggregates for selective detection of phenolic-nitroaromatic explosives and cell imaging

Abstract: Development of organic nanoparticles with high fluorescence, good biocompatibility along with strong resistance to photobleaching through simple synthetic routes is important for diverse applications such as sensing and bioimaging. Herein, we present the development of a pyrene excimer nanoaggregate which shows aggregation induced emission (AIE) effect in a solvent mixture of THF and water. The pyrene based fluorescent probe, dimethyl-5-(pyren-1-ylmethyleneamino)isophthalate (5-DP) was synthesized through a simple single step condensation reaction from inexpensive reagents. The photophysical studies of nanoaggregated system further corroborates the AIE active behavior of 5-DP probe at different water fractions (ƒw = 0% to 90%), where the hydrogen bonding interaction between imine and water molecules led to suppression of photoinduced electron transfer (PET) inducing significant enhancement in fluorescence. The highly photostable nanoaggregates were explored as a selective fluorescence “turn off” sensor for phenolic nitroaromatics and the chemo-selectivity was highly pronounced for 2,4,6-trinitrophenol (picric acid), that showed efficient quenching in aqueous as well as solid phase, with a detection limit of 10 nM in aqueous medium. The quenching efficiency of the nanoaggregates can be ascribed to a combination of factors including efficient fluorescence resonance energy transfer, inner filter effect and coulombic interaction between picric acid and the aggregated probe molecules. Further, random aggregation of the pyrene derivative could be controlled for the formation of fluorescent spherical nanoparticles using Pluoronics P-123 block copolymers as encapsulating agents. The resulting composite could be used as a neoteric cell imaging probe with significantly less cytotoxicity, thus showing their potential biological applications.

Meso Alkynylated Tetraphenylethylene (TPE) and 2,3,3-Triphenylacrylonitrile (TPAN) Substituted BODIPYs.

Abstract: The tetraphenylethylene (TPE) substituted BODIPY 2a, and 2,3,3-triphenylacrylonitrile (TPAN) substituted BODIPYs 2b and 2c were designed and synthesized by the Pd-catalyzed Sonogashira cross-coupling reaction. Their photophysical and electrochemical properties were investigated. The BODIPY 2a exhibits strong D–A interaction with poor fluorescence quantum yield. The BODIPYs 2b and 2c show red-shifted absorption and emission with higher fluorescence quantum yield compared to BODIPY 2a. The photonic properties of BODIPYs 2a–2c were compared with 4-ethynylbenzonitrile substituted BODIPY 3 and phenylacetylene substituted BODIPY 4. The results reveal that the electron donating group at the meso position of BODIPY blue shifts the absorption and emission with decreased fluorescence quantum yield, whereas the electron withdrawing group at the meso position of BODIPY red shifts the absorption and emission with enhanced quantum yields. The single crystal structures of BODIPYs 2a and 2b reflect the planar orientation...

Adaptive-Combining-Based Hybrid FSO/RF Satellite Communication With and Without HAPS

Abstract: In recent years, a growing interest has been witnessed in the usage of free space optics (FSO) link for satellite communication (SATCOM) scenarios, as it offers much higher data rates up to gigabits per second (Gbps) compared to existing radio frequency (RF) link. However, FSO links are sensitive to beam scintillation and pointing errors. In this paper, we consider a hybrid FSO/RF communication between ground station (GS) and satellite, where the RF link will act as a backup link to improve the reliability of FSO communication. In addition, we also consider high-altitude platform station (HAPS), which will act as a relay station, between GS and satellite to improve the end-to-end system performance. This has led to the development of space-air-ground integrated hybrid FSO/RF SATCOM networks. We analyse the performance of the proposed hybrid network considering an adaptive-combining-based switching scheme for both uplink and downlink scenarios with and without using HAPS as a relay station. In case of adaptive-combining-based switching scheme, the data is continuously transmitted over the FSO link, while maximal-ratio-combining (MRC) of RF and FSO links is performed when the quality of FSO link deteriorates. The performance analysis of adaptive-combining-based switching scheme in terms of outage and average symbol error rate (SER) is carried out and the same is compared with the single-link FSO SATCOM and single-threshold-based switching scheme proposed in the literature for hybrid FSO/RF SATCOM. In addition, the performance gain obtained by the proposed adaptive combining scheme over single-link FSO system for different channel conditions is also reported. Further, the asymptotic analysis is also carried out to obtain the diversity gain of the proposed system.